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Webster 1913 Edition

Adj.

Highest; uppermost;

as, the

topmost

cliff; the

topmost

branch of a tree

The nightngale may claim the

topmost

bough.

Cowper.

topmost ‎(comparative more topmost, superlative most topmost)

At or nearest to the top; uppermost; being the very highest.
- 2015, Seth Giolle, The Cane Stories
  While he worked to ply fingers back apart more than not, Kaiselan practised his crouch exploring the outpost's more topmost levels.

at or nearest to the top

German: oberst
Russian: са́мый ве́рхний ‎(sámyj vérxnij), наивы́сший (ru) ‎(naivýsšij) (often figurative), вы́сший (ru) ‎(výsšij) (often figurative)