Definition of dictionary

Short definition: The word dictionary means a book or online resource that lists words with their meanings, pronunciations, and examples. People use it to check definitions, spelling, and proper usage while reading, writing, or studying.

Looking for a clear and real-life explanation of the word dictionary? A dictionary is basically a place you go when you want answers about words: what they mean, how to spell them, how to pronounce them, and how to use them naturally in real sentences. It can be a physical book, a website, an app, or even a built-in tool inside a phone. Some dictionaries are simple and quick, while others go deep—showing multiple meanings, examples, synonyms, and notes about style, tone, or grammar. Below, each meaning is explained in a relaxed, natural way with long examples that reflect how people truly use this word.

Plural: dictionaries
Related: lexicon n., lexical adj., lexicography n.
Syllable: dic-tion-ar-y

1. (Noun) A reference book or online resource that lists words and explains their meanings, spelling, pronunciation, and usage.
   When she wasn’t sure what the word meant, she opened a dictionary and read not only the definition but also the example sentences to see how it’s used naturally.
   He keeps a small dictionary on his desk because he likes checking definitions while reading difficult books.
   Many people now use an online dictionary because it’s fast, searchable, and often includes audio pronunciation.

   Synonyms: wordbook, lexicon, reference book, glossary, vocabulary guide, language reference, word list, definition book, reference resource, spelling guide, language handbook, word reference
   Antonyms: novel, storybook, fiction book, poem collection, diary, personal journal, blank notebook, sketchbook, picture album, comic book, random writing, unstructured notes

2. (Noun) A specialized list of terms and meanings for a particular field, such as medicine, law, programming, or science.
   The student used a medical dictionary to understand technical terms that didn’t appear in normal everyday dictionaries.
   In programming, a data dictionary can explain what each field or variable represents, which makes a system easier to understand.
   Lawyers sometimes rely on a legal dictionary to make sure they interpret specific terms in the right way.

   Synonyms: technical glossary, terminology guide, specialist lexicon, field glossary, term reference, subject vocabulary, jargon guide, reference list, definitions manual, terminology handbook, reference glossary, subject dictionary
   Antonyms: general chat, casual talk, everyday conversation, informal speech, personal opinion, random guesses, vague wording, unclear explanation, nontechnical talk, everyday slang, unverified claims, loose language

3. (Noun) A book or tool that focuses mainly on translating words between two languages.
   He bought an English–Indonesian dictionary to help him translate words quickly while studying.
   A bilingual dictionary is useful, but you still need context to choose the best translation for the situation.
   She used a translation dictionary when writing emails, so her messages sounded more natural and polite.

   Synonyms: bilingual dictionary, translation dictionary, language translator book, phrase dictionary, word translation guide, two-language lexicon, translation reference, language bridge tool, multilingual dictionary, translation wordbook, phrasebook, translation glossary
   Antonyms: monolingual guide only, no-translation resource, picture-only book, silent reading, guessing meanings, learning without reference, speaking without help, pure immersion only, random interpretation, incorrect translation, misunderstanding, confusion

4. (Figurative) A trusted source that helps people “decode” meaning, not just for words but for concepts, symbols, or situations.
   For new employees, the team’s internal notes became a kind of dictionary that explained confusing terms and processes that nobody told them directly.
   His mentor was like a living dictionary, because he could explain complex ideas in simple, practical language.
   When you move to a new country, cultural experiences slowly become your dictionary, teaching you what gestures and expressions really mean in daily life.

   Synonyms: guide, key, decoder, reference, cheat sheet, explanation source, manual, handbook, roadmap, meaning guide, interpretive tool, clarity tool
   Antonyms: confusion, chaos, mystery, puzzle, uncertainty, misinterpretation, misinformation, lack of guidance, unclear source, misleading guide, wrong key, false explanation

5. (Modern usage) A built-in feature in apps, browsers, or phones that instantly shows definitions, spelling help, or pronunciation.
   He highlighted the word on his phone, and the built-in dictionary immediately showed the meaning and pronunciation.
   Many e-readers have a dictionary feature, so you can learn new words without leaving the page.
   She likes using a dictionary extension in her browser, because it makes reading English articles much easier.

   Synonyms: built-in dictionary tool, definition feature, lookup tool, word lookup, instant definition, dictionary app, online dictionary, word helper, vocabulary tool, pronunciation tool, meaning finder, word assistant
   Antonyms: no lookup, offline ignorance, no reference tool, manual guessing, reading without help, no definition access, no word support, no pronunciation aid, confusion only, unclear reading, misreading, misunderstanding