n. a foreign substance added to a material to alter its properties; -- a process used. e.g., in making semiconductors from pure silicon in the manufacture of semiconductor chips and integrated circuits. [ PJC ]
n. [ Endo- + parasite. ] (Zoöl.) Any parasite which lives in the internal organs of an animal, as the tapeworms, Trichina, etc.; -- opposed to
a. [ Levo- + DOPA, dihydroxyphenylalanine. ] (Chem. & Biochem.) A substance used as a therapy for Parkinson's Disease; the L form of Dopa; L-dihydroxyphenylalanine; L-hydroxytyrosine (