Where does “topmost” come from?

Topmost comes from Middle English toppe combined with Old English -mest, derived from Proto-Germanic tuppaz and ultimately Proto-Indo-European dumb-.

topmost (English): At or nearest to the top; uppermost; being the...

Definitions

Step	Language	Word	Meaning
1	English	top	The highest or uppermost part of something; A...
2	Middle English	top	The summit or top of something, especially a...
3	Old English	topp	—
4	Proto-West Germanic	*topp	—
5	Proto-Germanic	tuppaz	tuft, plait; top, summit
6	Proto-Indo-European	dumb-	tail, rod, staff, pole, penis; tail, rod, staff,...

topmost — Etymology, Origin & Word History | Etymology Explorer