semiarch

[ sem-ee-ahrch, sem-ahy- ]
/ ˈsɛm iˌɑrtʃ, ˈsɛm aɪ- /

noun

a half arch.

Origin of semiarch

First recorded in 1815–25; semi- + arch1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019