'microcline' originates from German, specifically the word 'Mikroklin', where 'mikro-' meant 'small' and '-klin' meant 'incline' or 'slope', referring to the small angle of inclination between the crystal axes.

'Mikroklin' was adopted into English as 'microcline' in the 19th century, and eventually became the modern English word 'microcline'.

Initially, it referred specifically to a feldspar mineral with a small deviation in its crystal structure, and this meaning has remained consistent in modern usage.