endonuclease: a nuclease that cleaves nucleic acids at interior bonds and so produces fragments of various sizes
nuclease: general term for enzymes that catalyze the hydrolysis of nucleic acid by cleaving chains of nucleotides into smaller units
mendelevium: a radioactive transuranic element synthesized by bombarding einsteinium with alpha particles (Md is the current symbol for mendelevium but Mv was formerly the symbol)