orthoclase

noun

or·​tho·​clase ˈȯr-thə-ˌklās 

-ˌklāz

: a monoclinic mineral of the feldspar group consisting of a silicate of potassium and aluminum

Word History

Etymology

German Orthoklas, from orth- + Greek klasis breaking, from klan to break — more at clast

First Known Use

1849, in the meaning defined above

Kids Definition

orthoclase

noun

or·​tho·​clase ˈȯr-thə-ˌklās 

-ˌklāz

: a mineral consisting especially of potassium feldspar