Webster's Revised Unabridged Dictionary · 1913

Molybdenum

Molybdenum , noun

[New Latin: compare French molybdène. See Molybdena.]

(Chemistry) A rare element of the chromium group, occurring in nature in the minerals molybdenite and wulfenite, and when reduced obtained as a hard, silver-white, difficulty fusible metal. Symbol Mo. Atomic number 42. Atomic weight 95.94.