What Is a Dictionary?
A dictionary is a reference work that lists words in a language, typically in alphabetical order, along with information about their meanings, pronunciation, etymology, and usage. At its most fundamental level, a dictionary serves as a bridge between a word and its meaning, providing readers with the tools to understand, spell, and correctly use the vocabulary of a language.
The word "dictionary" itself comes from the Medieval Latin dictionarium, derived from dictio, meaning "a word" or "a saying." This origin reflects the dictionary's primary function: to be a repository of words and their associated information. While most people think of a dictionary simply as a book that tells you what words mean, modern dictionaries are far more complex and nuanced than that simple description suggests.
A dictionary is not merely a list of definitions. A comprehensive dictionary entry typically includes the word's spelling, its phonetic pronunciation, its grammatical role (part of speech), one or more definitions, example sentences showing the word in context, information about the word's origin and historical development, and notes about usage or regional variations. Some dictionaries also include illustrations, cross-references to related terms, and frequency data showing how commonly the word is used.
Understanding what a dictionary is—and what it is not—is essential for anyone who uses language. A dictionary does not prescribe how people should speak; rather, most modern dictionaries describe how people actually speak and write. This distinction between prescriptive and descriptive approaches is one of the most important concepts in lexicography, the science and practice of dictionary-making.
Core Components of a Dictionary Entry
Every dictionary entry, whether in a printed volume or a digital database, consists of several key components. Understanding these components allows you to extract maximum value from any dictionary you use.
Headword (Lemma)
The headword is the main entry word, displayed in bold at the beginning of each entry. In English dictionaries, headwords are arranged alphabetically. The headword represents the base or canonical form of a word—for verbs, this is typically the infinitive; for nouns, the singular form. For instance, you would find "run" as a headword rather than "running" or "ran."
Pronunciation
Most dictionaries provide a guide to how the word is spoken. This may use the International Phonetic Alphabet (IPA), a proprietary pronunciation key, or respelling with familiar letter combinations. For example, the word "dictionary" might be transcribed as /ˈdɪkʃəˌnɛri/ in IPA. Understanding English pronunciation notation is a valuable skill for any dictionary user.
Part of Speech
Each entry indicates the word's grammatical function—whether it serves as a noun, verb, adjective, adverb, or another part of speech. Many words function as multiple parts of speech, and the dictionary entry will list all of them with their respective definitions. The word "run," for example, can be a verb ("I run every morning"), a noun ("She went for a run"), or an adjective ("a run-down building").
Definitions
The definitions are the heart of any dictionary entry. They explain the meaning or meanings of the word in clear, precise language. When a word has multiple senses, these are numbered and often arranged from most common to least common, or from oldest to newest meaning. Understanding what a definition is and how definitions are structured helps you navigate entries more efficiently.
Etymology
Many dictionaries include etymological information, tracing a word's historical origins and development. This section, usually enclosed in brackets, might tell you that a word comes from Latin, Greek, Old French, or another language. The study of word origins—known as etymology—can deepen your understanding of words and help you remember their meanings.
Usage Examples
Example sentences or phrases show the word being used in natural context. These examples help clarify meaning, demonstrate proper grammatical usage, and show the kinds of contexts in which the word typically appears. Learner's dictionaries tend to include more examples than standard dictionaries.
Usage Notes and Labels
Dictionaries often include labels such as "informal," "archaic," "technical," "British English," or "slang" to indicate the register, region, or domain where a word is typically used. Usage notes may also warn about commonly confused words or contested usages. Understanding the difference between formal and informal English helps you interpret these labels correctly.
Types of Dictionaries
Dictionaries come in many forms, each designed to serve different purposes and audiences. Understanding the types of dictionaries available can help you select the right tool for your needs.
General-Purpose Dictionaries
These are the dictionaries most people think of when they hear the word "dictionary." They aim to cover the general vocabulary of a language comprehensively. Examples include Merriam-Webster's Collegiate Dictionary, the Oxford English Dictionary (OED), and Collins English Dictionary. General-purpose dictionaries range from concise desk editions with 50,000–100,000 entries to unabridged volumes with over 400,000 entries.
Learner's Dictionaries
Designed specifically for people learning English as a second language, these dictionaries use simpler defining vocabularies, include more example sentences, and provide additional grammatical information. The Oxford Advanced Learner's Dictionary and the Longman Dictionary of Contemporary English are leading examples. They are invaluable for building vocabulary in a new language.
Bilingual Dictionaries
Bilingual dictionaries translate words between two languages. A Spanish-English dictionary, for example, helps Spanish speakers understand English words and vice versa. These dictionaries face the complex challenge of mapping meaning across languages where one-to-one correspondences rarely exist.
Specialized Dictionaries
These focus on particular subject areas, such as medical dictionaries, legal dictionaries, dictionaries of computing terms, or music dictionaries. They provide more detailed and technical definitions than a general dictionary can offer.
Historical Dictionaries
A historical dictionary traces the development of words over time, documenting when they first appeared, how their meanings have changed, and providing dated quotations that illustrate each stage of a word's life. The Oxford English Dictionary is the most famous historical dictionary of the English language.
Thesauruses
While technically distinct from dictionaries, thesauruses are closely related reference works that organize words by meaning rather than alphabetically. They list synonyms and antonyms for each entry, helping writers find the exact word they need. Understanding the difference between a dictionary and a thesaurus is important for effective language use.
A Brief History of Dictionaries
The history of dictionaries stretches back thousands of years. The earliest known word lists were Sumerian-Akkadian glossaries created around 2300 BCE in ancient Mesopotamia. These cuneiform tablets served as bilingual references for scribes who needed to work across languages.
In the Western tradition, early glossaries were created by medieval monks who wrote Latin definitions in the margins of difficult texts—a practice known as "glossing." These marginal notes were eventually compiled into separate glossary books called glossaria.
The first English dictionaries appeared in the early 1600s. Robert Cawdrey's A Table Alphabeticall (1604) is generally considered the first monolingual English dictionary, though it contained only about 2,500 "hard words" with brief definitions aimed at helping readers understand learned or borrowed terms.
The landmark moment in English lexicography came in 1755, when Samuel Johnson published his A Dictionary of the English Language. Johnson's dictionary contained approximately 42,773 entries, each with carefully crafted definitions and illustrative quotations from English literature. Johnson's work set the standard for serious lexicography and remained the preeminent English dictionary for over a century.
Across the Atlantic, Noah Webster published his An American Dictionary of the English Language in 1828. Webster's dictionary was motivated partly by a desire to establish a distinctly American form of English, and it introduced many of the spelling differences that distinguish American from British English to this day—"color" instead of "colour," "center" instead of "centre."
The most ambitious dictionary project in history began in 1857 when the Philological Society of London called for a comprehensive historical dictionary of English. The result, the Oxford English Dictionary, took over 70 years to complete its first edition (published in installments from 1884 to 1928). The OED aimed to trace every word in the English language from its earliest recorded use to the present, with dated quotations illustrating each sense. It remains the most comprehensive record of the English language's history.
How Dictionaries Are Created
Creating a dictionary is a monumental undertaking that requires the coordinated effort of dozens or even hundreds of lexicographers, editors, and support staff working over many years. The process is far more complex than most people realize.
Corpus Collection
Modern dictionaries are built on corpora—vast databases of real-world text collected from books, newspapers, magazines, websites, academic papers, transcribed speech, and other sources. A typical dictionary corpus contains billions of words. The corpus provides lexicographers with evidence of how words are actually used, ensuring that definitions reflect real usage rather than speculation.
Reading and Excerpting
Lexicographers systematically analyze the corpus, identifying new words, new senses of existing words, and shifts in usage patterns. Historically, this was done by human readers who manually copied interesting usages onto citation slips. Today, much of this work is assisted by computational tools that can detect patterns, track word frequencies, and flag emerging vocabulary.
Defining
Writing dictionary definitions is a specialized skill. Definitions must be accurate, concise, and intelligible to the dictionary's target audience. Lexicographers carefully analyze corpus evidence to determine the range of meanings a word carries, then craft definitions that capture each sense. The defining process also involves ordering multiple senses in a logical way and determining which senses are common enough to warrant inclusion.
Revision and Review
Dictionary entries undergo multiple rounds of review. Subject-matter experts may be consulted for technical terms, pronunciation specialists verify phonetic transcriptions, and etymologists check historical information. Senior editors review entries for consistency of style and accuracy.
Prescriptive vs. Descriptive Dictionaries
One of the most fundamental distinctions in lexicography is between prescriptive and descriptive approaches. This distinction shapes how dictionaries are made and how they should be interpreted.
A prescriptive dictionary aims to tell users how they should use language. It sets rules, identifies "correct" usage, and may label certain words or usages as "incorrect" or "nonstandard." Early dictionaries, including Johnson's, tended to be prescriptive in nature.
A descriptive dictionary aims to document how language is actually used by its speakers, without making judgments about correctness. Most modern dictionaries take a primarily descriptive approach, recording words and usages as they find them in real-world evidence. When new words enter the English language, descriptive dictionaries document them based on evidence of widespread use.
In practice, most dictionaries blend both approaches. While they primarily describe actual usage, they also include usage notes that alert readers to contested usages, regional differences, and formality levels. These notes help users make informed choices about their own language use without explicitly dictating what is "right" or "wrong."
"A dictionary is not a law book. It is a record of how language is used, not how some authority thinks it should be used." — Modern lexicographic principle
Why Dictionaries Matter
In an age of search engines and AI assistants, one might wonder whether dictionaries still matter. They do—profoundly—for several important reasons.
Standardization of Language
Dictionaries help establish and maintain standard forms of a language. While languages naturally vary across regions and communities (see English dialects and accents), dictionaries provide a common reference point that enables clear communication across these variations. Standardized spelling, in particular, depends heavily on dictionaries.
Education and Literacy
Dictionaries are fundamental educational tools. Learning how to use a dictionary is a skill taught in schools worldwide. For students developing their reading skills, dictionaries provide a way to independently discover the meanings of unfamiliar words, fostering self-directed learning and intellectual independence.
Professional Communication
In professional contexts—law, medicine, science, technology—precise language is essential. Specialized dictionaries ensure that professionals share a common understanding of technical terms, reducing the risk of miscommunication in high-stakes situations.
Cultural Record
Dictionaries serve as cultural artifacts, preserving the vocabulary of a language at a given point in time. Historical dictionaries, in particular, allow us to trace how societies have evolved by examining how their words have changed in meaning, which words have been coined, and which have fallen out of use. The study of words that changed meaning reveals fascinating insights about cultural shifts.
Language Learning
For the hundreds of millions of people learning English as a second language, dictionaries remain indispensable tools. They provide authoritative information about meaning, grammar, and usage that helps learners navigate the complexities of a new language. Online English dictionaries have made this resource more accessible than ever before.
The Digital Revolution and Dictionaries
The transition from print to digital has transformed dictionaries in profound ways. Digital dictionaries offer advantages that print editions simply cannot match.
Instant Access
Online dictionaries provide instant access to word information from any device with an internet connection. There is no need to physically find a book, guess which volume of a multi-volume set contains the word, or navigate guide words at the top of pages. A simple search delivers the entry in milliseconds.
Audio Pronunciation
Digital dictionaries can include audio recordings of words being spoken, making pronunciation guides far more accessible than phonetic transcriptions alone. This is especially valuable for learners who may not be familiar with IPA or other pronunciation notation systems.
Dynamic Updates
Print dictionaries become outdated the moment they are published. Digital dictionaries can be updated continuously, adding new words, revising definitions, and incorporating new usage evidence in real time. This is particularly important because language evolves constantly—new words emerge, existing words take on new meanings, and usage norms shift.
Cross-Referencing and Linking
Digital dictionaries can link entries to related words, making it easy to explore synonyms, antonyms, etymological relatives, and thematically connected vocabulary. This interconnected approach encourages deeper exploration of language.
Search Flexibility
While print dictionaries require you to know the spelling of a word to look it up, digital dictionaries offer wildcard searches, reverse lookups, phonetic searches, and other flexible search methods. If you know what a word means but cannot remember the word itself, some online tools can help you find it. You can even search for words by their roots, prefixes, and suffixes.
How to Choose the Right Dictionary
With so many dictionaries available, choosing the right one depends on your specific needs.
For General Reference
A reputable general-purpose dictionary like Merriam-Webster (American English) or Oxford Dictionary of English (British English) will serve most everyday needs. Both are available in print and online editions.
For Language Learners
If you are learning English, choose a learner's dictionary that provides simpler definitions, more example sentences, and detailed grammatical information. The Oxford Advanced Learner's Dictionary and Longman Dictionary of Contemporary English are excellent choices.
For Writers and Editors
Writers benefit from having both a comprehensive dictionary and a good thesaurus. Consider also a usage dictionary like Merriam-Webster's Dictionary of English Usage, which provides detailed guidance on contested or confusing usage points. Understanding grammar basics alongside dictionary use makes for stronger writing.
For Scholars and Researchers
For in-depth historical and etymological research, the Oxford English Dictionary is unmatched. For American English specifically, the Dictionary of American Regional English (DARE) is an invaluable resource for studying dialectal vocabulary.
For Specialized Fields
If you work in a specialized field, seek out a dictionary specific to your domain. Medical professionals, lawyers, engineers, and scientists all have access to dictionaries tailored to their fields' vocabularies.
Frequently Asked Questions
How many words are in the English language?
This is a surprisingly difficult question to answer because it depends on how you define "a word." The second edition of the Oxford English Dictionary contains about 600,000 entries, but many of these are archaic or highly technical. The most common English words—the ones used in everyday speech and writing—number only a few thousand.
How often are new words added to dictionaries?
Major dictionaries add hundreds to thousands of new words each year. For instance, Merriam-Webster and Oxford regularly announce batches of new additions. Before a word is added, lexicographers look for sustained, widespread use across multiple sources over a period of time. The process of how new words enter the dictionary is methodical and evidence-based.
What is the difference between a dictionary and an encyclopedia?
A dictionary focuses on words themselves—their meanings, spellings, pronunciations, and grammatical properties. An encyclopedia focuses on things—providing detailed information about subjects, people, places, events, and concepts. A dictionary entry for "photosynthesis" would define the word; an encyclopedia entry would explain the scientific process in detail.
Can a word be removed from the dictionary?
In practice, words are rarely removed from dictionaries, especially historical ones. However, in abridged or concise editions, editors may choose not to include words that have fallen out of common use in order to make room for new entries. In unabridged and historical dictionaries, even obsolete words are retained as part of the historical record.
Who decides what goes in a dictionary?
Lexicographers—the specialists who write and edit dictionaries—make these decisions based on evidence from language corpora. They look for words that are used by many people, across multiple sources, over a sustained period. No single person or committee "approves" words; the evidence of real-world usage is the primary criterion.