1. division of a whole into parts.

2. in linguistics, the process through which a hearer separates speech into a sequence of identifiable words and phonemes.

3. the division of an animal’s body into a number of similar compartments (segments or metameres). Metameric segmentation is most apparent in annelid worms, in which the arrangement of muscles, blood vessels, nerves, and so on recurs in each segment.

4. see cleavage.