myosin

noun

my·​o·​sin ˈmī-ə-sən 

: a fibrous globulin of muscle that can split ATP and that reacts with actin in muscle contraction to form actomyosin

Examples of myosin in a Sentence

Recent Examples on the Web

The team behind the new development mimicked the function of myosin for their actuator. — Chris Young, Interesting Engineering, 5 Aug. 2025

These calcium ions activate another type of protein filament called myosin that induces the cell to move. — Yizeng Li, The Conversation, 9 Jan. 2023

Our muscles contract when a protein called myosin climbs along a microfibre, crunching it more tightly—each step along the fibre costs one ATP. — James Somers, The New Yorker, 25 Oct. 2022

The tail region varies in length and composition depending on the myosin type and is responsible for dimerization or for binding to cargo such as vesicles or other cellular components. — Encyclopedia Britannica, 3 Apr. 2026

Word History

Etymology

International Scientific Vocabulary my- + -ose entry 2 + -in entry 1

First Known Use

1942, in the meaning defined above

Rhymes for myosin

• actomyosin
• tropomyosin
• niacin

Kids Definition

myosin

noun

my·​o·​sin ˈmī-ə-sən 

: a protein of muscle that with actin is active in muscular contraction

Medical Definition

myosin

noun

my·​o·​sin ˈmī-ə-sən 

1

: actomyosin

2

: a fibrous globulin of muscle that can split ATP and that reacts with actin to form actomyosin