actin and myosin are myofillaments that make up myofibrils (part of a muscle fibre)(so therefore : muscle is an actin or myosin containing structure
Myofilaments Actin, which constitutes about 25 percent of the protein of myofilaments, is the major component of the thin filaments in muscle (per Encyclopedia Britannica...
The basic unit of muscular contraction; the sarcomere.
myofibril
Myofibirl