IPA: /ˈbɒtəmˌməʊst/
KK: /ˈbɑːtəmˌmoʊst/
The lowest or last in position, rank, or importance; situated at the very bottom.
The bottommost shelf in the cabinet is hard to reach.
Bottommost → It is formed from "bottom" (from Old English "bōtm", meaning the lowest part or base) and "-most" (meaning the furthest or extreme). The word "bottommost" refers to the very lowest part or position of something.
Think of the 'lowest part' ('bottom') and the 'furthest' ('-most') to remember that 'bottommost' means the very lowest position.
No commonly confused words.