Definition of "myosin" [my•o•sin]

• The commonest protein in muscle cells, responsible for the elastic and contractile properties of muscle. It combines with actin to form actomyosin. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The motor protein myosin, for example, is involved in the the contraction of muscle fibers in animals."
• "Every technical explanation in the literature (that iv'e seen) as to why myosin is a motor referrs to the actual definition of a motor."
• "When myosin is activated, the contractile filaments slide apart and the muscle cell relaxes."