A stitch is a single element of a thread laid by a threaded needle when sewing through the fabric. The thread can consist of one or more threads that are linked or intertwined.
Source:
Schlums, Ulla; Dressler, Heike; Decker, Sonja (2022), Fertigung Bekleidung, 1. Auflage, Haan-Gruiten: Verlag Europa-Lehrmittel, S. 50