The Collaborative International Dictionary of English v.0.48:
Coaction \Co*ac"tion\, n. [L. coactio.] Force; compulsion, either in restraining or impelling. --Sojth. [1913 Webster]WordNet (r) 3.0 (2006):
coaction n 1: act of working jointly; "they worked either in collaboration or independently" [syn: collaboration, coaction]