Definition of rear arch in English:

rear arch

noun

Architecture
  • Especially in Gothic architecture: the inner arch of a window or doorway, typically differing in size or form from the external arch.

Origin

Mid 19th century; earliest use found in George Ayliffe Poole (1809–1883), Church of England clergyman and author. From rear- + arch.

Pronunciation

rear arch

/ˈrɪər ɑːtʃ/