topic āļāļ·āļāļāļ°āđāļĢ topic āļāļ·āļāļāļ°āđāļĢ Linguistics A word or phrase in a sentence, usually providing information from previous discourse or shared knowledge, that the rest of the sentence elaborates or comments on. Also called theme.The subject of a speech, essay, thesis, or discourse.A subject of discussion or conversation.A subdivision of a theme, thesis, or outline. See Synonyms at subject.