[cer.tain.ty] n, pl -ties (14c) 1: something that is certain
2: the quality or state of being certain esp. on the basis of evidence syn certainty, certitude, conviction mean a state of being free from doubt. certainty and certitude are very close; certainty may stress the existence of objective proof "claims that cannot be confirmed with scientific certainty", while certitude may emphasize a faith in something not needing or not capable of proof "believes with certitude in an afterlife". conviction applies esp. to belief strongly held by an individual "holds firm convictions on every issue".