回头 literally means 'to turn one's head back' — combining 回 (huí, 'to return, to turn') and 头 (tóu, 'head'). As a verb, it describes the physical action of turning your head to look behind you or in another direction. It’s often used in everyday speech to signal awareness, checking, or reconsideration — for example, when someone glances back while walking or pauses to reflect.

As an adverb, 回头 means 'later', 'in a little while', or 'at some point in the future', carrying a casual, conversational tone. This usage stems from the idea of 'turning back (to something) later'. It commonly appears in spoken Chinese and informal writing, especially in promises, suggestions, or deferred actions ('I’ll call you back later' → 我回头给你打电话). Unlike formal time expressions like 稍后 or 之后, 回头 feels relaxed and personal.