dictionary

American  

[dik-shuh-ner-ee] / ˈdɪk ʃəˌnɛr i /

noun

plural

dictionaries

1. a book or digital resource (such as Dictionary.com) containing a selection of words and information about their meanings, pronunciations, etymologies, inflected forms, derived forms, etc., in either the same or another language; lexicon; glossary.

   an unabridged dictionary of English;

   a Japanese–English dictionary.

2. a book or digital resource giving information on a particular subject or on a particular class of words, names, or facts, usually arranged alphabetically.

   a biographical dictionary;

   a dictionary of mathematics.

3. Computers.

   1. a list of codes, terms, keys, etc., and their meanings, used by a computer program or system.

   2. a selection of words used by a piece of software, such as a word-processing program, to check the spelling of text entered.

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dictionary British  

/ ˈdɪkʃənərɪ, -ʃənrɪ /

noun

1. 1. a reference resource, in printed or electronic form, that consists of an alphabetical list of words with their meanings and parts of speech, and often a guide to accepted pronunciation and syllabification, irregular inflections of words, derived words of different parts of speech, and etymologies

   2. a similar reference work giving equivalent words in two or more languages. Such dictionaries often consist of two or more parts, in each of which the alphabetical list is given in a different language

      a German-English dictionary

   3. ( as modifier ) See also glossary lexicon thesaurus

      a dictionary definition

2. a reference publication listing words or terms of a particular subject or activity, giving information about their meanings and other attributes

   a dictionary of gardening

3. a collection of information or examples with the entries alphabetically arranged

   a dictionary of quotations

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Etymology

Origin of dictionary

First recorded in 1570–80; from Medieval Latin dictiōnārium, dictiōnārius, from Late Latin dictiōn- stem of dictiō “word” + -ārium, -ārius adjective and noun suffix; see diction ( def. ), -ary ( def. )

Explanation

A dictionary is a collection of words and their definitions (and sometimes other information). Such collections are usually printed as books, but some are now designed for use on computers. Dictionary originally came from the Latin word dictionarius, meaning "a manual or book of words." A dictionary is most commonly used to look up the definitions of particular words, but other information, such as etymology and usage guidelines, often appears as well. Electronic dictionaries can include even more information, like slang and popular texting acronyms, such as "ttyn," which stands for "talk to you never."

Example Sentences

The brilliantly passive-aggressive faux talk show “Between Two Ferns With Zach Galifianakis” was web-based, but that’s defined as TV in my dictionary.

From Los Angeles Times • Apr. 22, 2026

I know, I know, the only place where success comes before work is in the dictionary.

From Salon • Apr. 13, 2026

In the early 1900s, defining color in the dictionary required the expertise of a scientist.

From The Wall Street Journal • Mar. 27, 2026

She pointed to the “ordinary meaning” and dictionary definition of the word regulate, arguing that the power to tax and raise revenue cannot fairly be made to fit within these definitions.

From Slate • Mar. 4, 2026

The whole room got very quiet and I was glad, now, that at the last minute I had looked up resourceful in the dictionary.

From "The Best School Year Ever" by Barbara Robinson

Related Words

• glossary
• language
• vocabulary