An Etymological Dictionary of Astronomy and Astrophysics

Plural form: vertices.

1. Astro.: A point in the → celestial sphere toward which or from which the common motion of a group of stars is directed.
   

2. Math.: The → point where two → sides of a → plane figure or an → angle  → intersect.
   

3. In → graph theory, any of the points of which graphs are formed. Same as → node.

Etymology (EN): From L. vertex “highest point,” literally “the turning point,” originally “whirlpool,” from vertere “to turn,” cognate with Pers. vartidan, gardidan, → version.

Etymology (PE): Târak, variant târ “top, vertex, head, the middle of the head;” cf. Sogd. târ “summit, forehead;” Yaghnobi tôr(k) “the back of the head;” Yazghulami tur “summit, head;” Proto-Ir. *starH- “to spread,” → expand; PIE *ster- “spread, extend.”