undercity (English) comes from English city, from Middle English cite, from Old French citet, from Latin cīvitās, from Proto-Italic keiwis, from Proto-Indo-European ḱey- — to be lying down; to settle.
undercity (English): A subterranean city
Definitions
A subterranean city
Ancestry of “undercity”, step by step
undercity traces back through two separate lines of ancestry.