n. [ Fibrin + Gr. &unr_; to form, mold. ] (Physiol.Chem.) An albuminous substance, existing in the blood, which in combination with fibrinogen forms fibrin; -- called also
n. [ Gr. &unr_; to form, mold. ] (Biol.) A substance associated with nuclein in cell nuclei, and by some considered as the fundamental substance of the nucleus. [ 1913 Webster ]