ETYM Latin sessilis low, dwarf, from sedere, sessum, to sit: cf. French sessile.
1. (Biology) Attached directly by the base; not having an intervening stalk; SYN. stalkless.
2. (Biology) Permanently attached to a substrate; not free to move about; SYN. attached.
3. Stalkless, sedentary, fixed or stationary.
Attached by base without a stalk; attached permanently.
In botany, a leaf, flower, or fruit that lacks a stalk and sits directly on the stem, as with the sessile acorns of certain oaks. In zoology, it is an animal that normally stays in the same place, such as a barnacle or mussel. The term is also applied to the eyes of crustaceans when these lack stalks and sit directly on the head.