imbē

noun. deep valley, wide ravine

imbi

preposition. between

mīni

preposition. between

yag

root. gap, gap; [ᴹ√] yawn, gape

This root appeared as ᴹ√YAG “yawn, gape” in The Etymologies of the 1930s with derivatives like ᴹQ. yáwe/N. iau “ravine, cleft, gulf” and N. ia “gulf”, the last of these the final element in N. Moria (Ety/YAG). The root √YAG was mentioned several times in Tolkien’s later writings, usually in connection to S. Moria (Let/383; PE17/35, 42). In one place it was given the gloss “gap” (PE17/42).