IPA: /ˌsɛmɪˈluːnər/
KK: /sɛməˈlunər/
Having the shape of a half-moon or crescent.
The semilunar shape of the arch made the building look elegant.
Semilunar → It is formed from "semi-" (meaning half) and "lunaris" (from Latin "luna", meaning moon). The word "semilunar" refers to something that is half-moon shaped or resembling a half-moon.
Think of 'half' ('semi-') of a 'moon' ('luna') to remember that 'semilunar' describes something that looks like a half-moon.
No commonly confused words.