'pinnacle' originates from Latin, specifically the word 'pinnaculum,' where 'pinna' meant 'feather, wing, or battlement' and the diminutive suffix '-culum' indicated a small or projecting object.

'pinnaculum' passed into Old French (as 'pinnacle') and Anglo-Norman, then into Middle English as 'pinnacle', eventually becoming the modern English word 'pinnacle'.

Initially, it referred to a small winglike or projecting part (such as a battlement or small ledge), but over time it evolved to mean a pointed architectural ornament and figuratively the 'highest point' or 'culmination'.