myofilament
/ˌmʌɪə(ʊ)ˈfɪləm(ə)nt/Histology and Physiology
noun
Any of the ultramicroscopic, rod-like aggregates of protein molecules that are arranged in an overlapping array in the sarcomere of a myofibril, occurring in two forms, the thick filament (composed of myosin molecules) and thin filament (composed of actin molecules).
Origin
1940s; earliest use found in Journal of Clinical Investigation. From myo- + filament.