A little wing, (Matthew 4:5; Luke 4:9). On the southern side of the temple court was a range of porches or cloisters forming three arcades. At the south-eastern corner the roof of this cloister was some 300 feet above the Kidron valley. The pinnacle, some parapet or wing-like projection, was above this roof, and hence at a great height, probably 350 feet or more above the valley.

Noah Webster's New International Dictionary of the English Language

1. (n.) The topmost point; the peak of a structure or mountain; 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.

2. (n.) Anything resembling a pinnacle; a lofty peak; a pointed summit.

3. (v. t.) To build or furnish with a pinnacle or pinnacles.