Definition of pinnacle

• n. - An architectural member, upright, and generally ending in a small spire, -- used to finish a buttress, to constitute a part in a proportion, as where pinnacles flank a gable or spire, and the like. Pinnacles may be considered primarily as added weight, where it is necessary to resist the thrust of an arch, etc.
• n. - Anything resembling a pinnacle; a lofty peak; a pointed summit.
• v. t. - To build or furnish with a pinnacle or pinnacles.