millisite

noun

mil·​lis·​ite

ˈmilə̇ˌsīt

plural -s

: a mineral (Na,K)CaAl₆(PO₄)₄(OH)₉.3H₂O consisting of a basic hydrous phosphate of sodium, potassium, calcium, and aluminum

Word History

Etymology

F. T. Millis, 20th century American mineral collector + English -ite

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now