factor ii factor i • factor iii · · · Info · Definitions · Synonyms · Characters · · factor ii · · Text Common · · Latin · · Scripts 9 · · Length 4 · · Syllables Definitions · · · (noun) a protein in blood plasma that is the inactive precursor of thrombin. Synonyms: prothrombin, factor II. · · Noun Definition 1 Synonyms · · · prothrombin · · Synonym 1 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 f latin small letter f U+0066 i latin small letter i U+0069 o latin small letter o U+006F r latin small letter r U+0072 t latin small letter t U+0074