tantalum: Meaning and Definition of

tan•ta•lum

1. a gray, hard, rare, metallic element occurring in columbite and tantalite and usually associated with niobium: used, because of its resistance to corrosion by most acids, for chemical, dental, and surgical instruments and apparatus. Symbol: Ta; at. wt.: 180.948; at. no.: 73; sp. gr.: 16.6.