IPA: /ˈnɛðərˌmoʊst/
KK: /ˈnɛðərˌmoʊst/
The lowest or deepest part of something.
The treasure was hidden in the nethermost depths of the cave.
Nethermost is formed from "nether" (from Old English "nither", meaning lower or beneath) and "-most" (meaning the most or furthest). The word "nethermost" refers to the lowest or deepest part of something.
Think of 'nether' meaning lower, and '-most' indicating the furthest point — together, they help you remember that 'nethermost' means the lowest point.