I. ˈ ̷ ̷(ˌ) ̷ ̷+ˌ- noun
Etymology: Latin semicirculus, from semi- + circulus circle — more at circle
1.
a. : the part of a circle from one end of a diameter to the other : an arc equal to one half of a circumference : half circle — called also semicircumference
b. : either half of a circular area divided diametrically
2. : a body, formation, or arrangement of objects in the form of half of a circle or half of a circumference
3. : an instrument of semicircular form used especially for measuring angles
II. transitive verb
: to form or throw into a semicircle : surround with a semicircle
the port semicircles a blue bay — Sylvia Martin
intransitive verb
: to become a semicircle : move in a semicircle