certain

/ˈsər-tᵊn/

Middle English certeyn, certayne, borrowed from Anglo-French certein, certain, going back to Vulgar Latin *certānus, from Latin certus "fixed, settled, indisputable," originally past participle of cernere "to sift, discern, decide, determine" (going back to an Indo-European present stem *kri-n-, verbal adjective *kri-to-, from a verbal base *krei̯̯̯(h)- "sift, separate," whence Greek krī́nein "to separate, choose, decide," verbal adjective kritós, Welsh gogrynu "to sift") + -ānus +

adjective

  1. fixed, settled

  2. of a specific but unspecified character, quantity, or degree

  3. dependable, reliable

a certain percentage of the profit

sure certain positive cocksure mean having no doubt or uncertainty. sure usually stresses the subjective or intuitive feeling of assurance. certain may apply to a basing of a conclusion or conviction on definite grounds or indubitable evidence.

pronoun

  1. certain ones

certain of my generation

French phrase

  1. of a certain age : no longer young