Wiktionary:Word of the day/July 31

1. The topmost point or surface of a thing; the apex, the peak.
   1. The highest point of a hill, mountain, or similar geographical feature.
   2. (mathematics) A vertex of a polygon or polyhedron.
   3. (nautical, rail transport, road transport) The highest point of a canal, railway, road, etc.
   4. (obsolete)
      1. (botany) Synonym of anther (“the pollen-bearing part of the stamen of a flower”); also (rare), synonym of stigma (“the sticky part of a flower that receives pollen during pollination”)
      2. (crystallography, rare) One of the two vertices of a crystal with a rhombohedral shape where the angles of each face are equal; also, the highest point of a crystal with a pyramidal or tetrahedral shape.
2. (figurative)
   1. The highest point of achievement, development, etc., that can be reached; the acme, the pinnacle.
   2. (politics)
      1. (archaic) The highest level of political leadership.
      2. (by extension) An assembly or gathering of the leaders of countries to discuss issues of international significance; also (loosely), an important or high-level gathering or meeting.

summit v

1. (transitive, climbing, informal) To reach the summit (noun sense 1.1) of (a mountain).
2. (intransitive)
   1. (climbing, informal) To reach the summit of a mountain.
   2. (politics) To attend a summit (noun sense 2.2.2).

The mountaineers Achille Compagnoni and Lino Lacedelli, who were members of an Italian expedition, became the first people to reach the summit of K2—the second highest mountain in the world—on this day 70 years ago in 1954.