口头 (kǒu tóu) is an adjective meaning 'oral' or 'spoken', describing something communicated by speech rather than in writing. Literally, 口 means 'mouth' and 头 means 'head' — together they evoke the idea of communication originating from the mouth/head region, emphasizing spoken expression. It's commonly used to modify nouns like 通知 (notice), 协议 (agreement), 承诺 (promise), or 考试 (exam), indicating that the action or content is delivered verbally.

This term appears frequently in formal and informal contexts — for instance, in workplaces (e.g., a manager giving a 口头指示), schools (e.g., 口头报告), or daily conversations (e.g., confirming plans orally). Unlike written forms, 口头 communication is immediate but not legally binding unless later documented. It carries neutral register but can imply informality or lack of permanence, so speakers often clarify whether something is 'just oral' or will be followed up in writing.