Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
sessile is an adjective meaning "permanently attached to a substrate; not free to move about". It carries 2 recorded senses.
permanently attached to a substrate; not free to move about
“sessile marine animals and plants”
biology
attached directly by the base; not having an intervening stalk
“sessile flowers”
“the shell of a sessile barnacle is attached directly to a substrate”
biology
Definitions, synonyms and semantic relations for sessile come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.