- vertex, peak, apex, acme - the highest point (of something); "at the peak of the pyramid"
--1 is a kind of extreme point, extreme, extremum
--1 has particulars: crown; roof peak - apex, solar apex, apex of the sun's way - the point on the celestial sphere toward which the sun and solar system appear to be moving relative to the fixed stars
--2 is a kind of celestial point
--2 is a part of
Antonyms: antapexcelestial sphere, sphere, empyrean, firmament, heavens, vault of heaven, welkin