noun
The set of letters used when writing in a language.
A writing system in which letters represent phonemes. (Contrast e.g. logography, a writing system in which each character represents a word, and syllabary, in which each character represents a syllable.)
(computer science) A typically finite set of distinguishable symbols.
(India, Hong Kong, Singapore, Malaysia) An individual letter of an alphabet; an alphabetic character.
The simplest rudiments; elements.
(Internet slang, politics) An agent of the FBI, the CIA, or another such government agency.
verb
(rare) To designate by the letters of the alphabet; to arrange alphabetically.