wafer

UK: /ˈweɪfə^r/ US: /ˈweɪfɚ/ ,(wā′fər)

WordReference Random House Learner's Dictionary of American English © 2026

wa•fer /ˈweɪfɚ/   n. [countable]

1. Food a thin, crisp cake, cookie, biscuit, or candy.
2. Religion a thin disk of unleavened bread used in the Eucharist.
3. any small, thin disk.

wa•fer•like, adj. 

WordReference Random House Unabridged Dictionary of American English © 2026

wa•fer  (wā′fər), n. 

1. Food a thin, crisp cake or biscuit, often sweetened and flavored.
2. a thin disk of unleavened bread, used in the Eucharist, as in the Roman Catholic Church.
3. a thin disk of dried paste, gelatin, adhesive paper, or the like, used for sealing letters, attaching papers, etc.
4. Medicine a thin sheet of dry paste or the like, used to enclose a powder to be swallowed.
5. any small, thin disk, as a washer or piece of insulation.
6. Electronics a thin slice of semiconductor used as a base material on which single transistors or integrated-circuit components are formed.

v.t. 

7. to seal, close, or attach by means of a wafer or wafers:
   to wafer a letter.

• Middle Dutch wafer, variant of wafel waffle¹
• Middle English wafre 1350–1400

wa′fer•like′, wa′fer•y, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

wafer / ˈweɪfə/ noun

1. a thin crisp sweetened biscuit with different flavourings, served with ice cream, etc
2. a thin disc of unleavened bread used in the Eucharist as celebrated by the Western Church
3. an envelope of rice paper enclosing a medicament
4. a large single crystal of semiconductor material, such as silicon, on which numerous integrated circuits are manufactured and then separated
5. a small thin disc of adhesive material used to seal letters, documents, etc

verb

1. (transitive) to seal, fasten, or attach with a wafer

Etymology: 14th Century: from Old Northern French waufre, from Middle Low German wāfel; related to waffle¹

ˈwafer-ˌlike, ˈwafery adjective