[pin-uh-kuh
l] 
noun, verb, -cled, -cling.| 1. | a lofty peak. |
| 2. | the highest or culminating point, as of success, power, fame, etc.: the pinnacle of one's career. |
| 3. | any pointed, towering part or formation, as of rock. |
| 4. | Architecture. a relatively small, upright structure, commonly terminating in a gable, a pyramid, or a cone, rising above the roof or coping of a building, or capping a tower, buttress, or other projecting architectural member. |
| 5. | to place on or as on a pinnacle. |
| 6. | to form a pinnacle on; crown. |
| pin·na·cle (pĭn'ə-kəl) n.
[Middle English, from Old French, from Late Latin pinnāculum, diminutive of Latin pinna, feather; see pet- in Indo-European roots.] |
Pinnacle
a little wing, (Matt. 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.
pinnacle
in architecture, vertical ornament of pyramidal or conical shape, crowning a buttress, spire, or other architectural member. A pinnacle is distinguished from a finial by its greater size and complexity and from a tower or spire by its smaller size and subordinate architectural role. A tower may be decorated with pinnacles, each one capped by a finial.
Learn more about pinnacle with a free trial on Britannica.com.