mendelevium /(mĕn*dĕ*lē"vē*ŭ/m)/

men·de·le·vi·um

mendelevium

a.
  1. an unstable radioactive element discovered in 1955 and produced artificially only in very small quantities; symbol Md (also Mv). It is a transuranic element with atomic number 101. Isotopes 255, 256, 257, and 258 have been prepared. Md258, the longest-lived, has a half-life of two months. (Chem.)