'Upmost' definitions:

Definition of 'upmost'

(from WordNet)
adjective
At or nearest to the top; "the uppermost book in the pile"; "on the topmost step" [syn: topmost, uppermost, upmost]

Definition of 'Upmost'

From: GCIDE
  • Upmost \Up"most`\, a. [Cf. Uppermost.] Highest; topmost; uppermost. --Spenser. Dryden. [1913 Webster]