SES'SILE, adjective [Latin sessilis. See Set.] In botany, sitting on the stem. A sessile leaf issues directly from the stem or branch, without petiole or footstalk. A sessile flower has no peduncle. Sessile pappus or down has no stipe, but is placed immediately on the seed.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI