actin Syllabification: (ac·tin)Pronunciation: /ˈaktən/Definition of actin noun Biochemistry a protein that forms (together with myosin) the contractile filaments of muscle cells, and is also involved in motion in other types of cells. Origin: 1940: from Greek aktis, aktin- 'ray' + -in1actin in other Oxford dictionaries Definition of actin in the British & World English dictionary
