penniform
/ˈpɛnɪfɔːm/Anatomy and Biology
adjective
Resembling a feather; specifically (of a muscle) having fibres attached to a tendon like the barbs of a feather to the rachis.
Origin
Early 18th century. From post-classical Latin penniformis (G. A. Borelli De Motu Animalium I. xv. 123) from penna feather + -formis.