Trite but true: Professional translators don’t translate words or sentences but texts. In the era of translation memories, it becomes more and more difficult to produce a coherent text that fulfils the functions required by the translation brief. After briefly looking at some traditional definitions of the translation unit (TU), this paper suggests a functional way of looking at the concept. We note that each text consists of several lower-level units intended to achieve particular communicative functions, which are indicated by what I call “function markers” on various linguistic and non-linguistic ranks. In one particular text, for example, irony can be marked by a contradiction between the utterance and the situation, on the pragmatic level, by two parallelisms, on the level of syntax, by a hyperbolic adjective, on the word level, by a particular intonation, on the prosodic level, and, nonverbally, by the speaker’s raised eyebrow. All these markers form a “vertical translation unit”.