IPA: /ˈrɪərˌmoʊst/
KK: /ˈrɪrˌmoʊst/
The position that is the furthest back or last in a line or arrangement.
The rearmost car in the convoy was difficult to see.
Rearmost → It is formed from "rear" (from Old English "raer", meaning back or behind) and "most" (from Old English "mōst", meaning greatest or most). The word "rearmost" means the furthest back or the most behind in position.
Think of being at the 'back' ('rear') and the 'greatest' distance behind ('most') — that's why rearmost means the furthest back.