molybdenum

noun2

1. •
   A chemical element (symbol Mo) with an atomic number of 42: a silvery metal, not found as a free element, used in steel alloys.

   • At pH levels below 5, wheat yields may be low, molybdenum may become unavailable to plants, and other trace elements may be concentrated to toxic levels. — 1990
2. •
   A single atom of this element.