(phonetics) A written symbol used systematically for denoting a phoneme or any other phonetic quality in utterance.

(logic) A formal system of deductive logic in which aspects and relationships of natural language are represented by a system of symbols.

(literary) The leek as an emblem of Wales. / (geology) A specific symbol printed on geologic maps, Ꞓ, which denotes any Cambrian-age formation.

(computing theory) A symbol in a formal grammar that cannot appear in sentences of the grammar but may eventually be resolved into a sequence of terminal symbols.

A unique series of letters assigned to a company or other security for trading purposes.