fibrin fibrillous • fibrinase · · · Info · Definitions · Characters · · fibrin · · Text Latin · · Script 6 · · Length 2 · · Syllables Definitions · · · (noun) a white insoluble fibrous protein formed by the action of thrombin on fibrinogen when blood clots; it forms a network that traps red cells and platelets. · · Noun Definition 1 Characters · · b latin small letter b U+0062 f latin small letter f U+0066 i latin small letter i U+0069 n latin small letter n U+006E r latin small letter r U+0072