clinopyroxenePronunciation: /ˌklʌɪnə(ʊ)pʌɪˈrɒksiːn/Definition of clinopyroxene noun [mass noun] a mineral of the pyroxene group crystallizing in the monoclinic system. Origin: early 20th century: from clino- in the sense 'monoclinic' + pyroxeneclinopyroxene in other Oxford dictionaries Definition of clinopyroxene in the US English dictionary