collagen, collagenous Any of various tough, fibrous proteins found in bone, cartilage, skin, and other connective tissue of vertebrates. Boiling with water converts collagen to gelatin. Collagens have great tensile strength, and provide these body structures with the bility to withstand forces that stretch them. Collagens consist of three polypep... Found on http://www.wordinfo.info/words/index/info/view_unit/523/