noun
dictionary
DIHK-shuh-nuh-ree
noun
1
A reference book that lists words alphabetically along with their meanings, pronunciations, and other details.
"She looked up the word in an online dictionary."
"The old dictionary on the shelf was falling apart from years of use."
2
In computing, a data structure that stores values under unique keys for quick lookup.
"The program stores user settings in a dictionary keyed by username."
How to Use Dictionary
Learner’s notesIn plain EnglishA book (or app, or data structure) that looks things up by matching a word or key to its meaning or value.
Common pairings
look it up in a dictionary
a pocket dictionary
a dictionary entry
Word Forms
dictionaried past tense, dictionaries plural, dictionaries singular
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She looked up the word in an online _____.
Etymology
From Medieval Latin dictionarium, built on Latin dictio ("a speaking, a word") plus -arium, meaning "a place for."