There are many different things it could be called. It would depend on the type of muscle, the location, whether or not it is pathologic, and whether or not it is cancerous. For instance a benign smoth muscle tumor in the uterus is a leiomyoma (fibroid), but a cancerous skeletal muscle tumor is a rhabdomyosarcoma.
If you want a more concise or more precise answer then - would need a little more information.
Myoanatomy is the medical term meaning structure of a muscle. It may also mean the study of muscle structure.
Dystonia is the medical term meaning bad muscle tone.
Contraction is the medical term meaning the normal shortening or tightening of a muscle.
Myopathy is the medical term meaning disease of the muscle. my/o- muscle; pathy-disease
muscle hypertrophy
Dystonia is a medical term meaning abnormal muscle tone.
Myotomy is the medical term meaning the surgical removal of part of a muscle.
No such specific medical term
Atrophy.
Myocardial infarction is the medical term meaning damage to the heart muscle.
The insertion is the end of the muscle. The origin is the beginning.
cyc- is the combining form meaning ciliary muscle, as in iridocyclitis.