proto noun 2adjective 1forms 1 noun2 •(informal) A prototype of a design.[…] attending various fabric trade shows across the country and internationally; reviewing protos (prototypes) and strike-offs; approving final designs; and communicating with overseas mills. — 2013 •(informal, slang) A protogen. adjective1 •Clipping of prototypical; preceding the proper beginning of something.[…] he photographed his tenant, the proto male supermodel Matt Collins, for Italian Harper’s Bazaar. — 2007 formsprotos
