A narrow or constricted segment of the body of an insect. Used especially to refer to the metasomal segment of Hymenoptera such as wasps. Alternate form: pedicel
In a simple leaf, the petiole is the structure that attaches the leaf blade to the stem In a palmately compound leaf, the petiole attaches the leaflets to the stem In a pinnately compound leaf, the petiole attaches the leaflets to the rachis, which in turn attaches to the stem