D defs.my
Entry 3 senses Webster, 1913

Certainty

/sẽrt'-ən-tē/ · Cer·tain·ty · IPA /ˈsɝtn̩ti/
01 n. The quality, state, or condition, of being certain.
pl. Certainties ((#))
  1. 1.
    The quality, state, or condition, of being certain.
    “The certainty of punishment is the truest security against crimes.” — Fisher Ames.
  2. 2.
    A fact or truth unquestionable established.
    Certainties are uninteresting and sating.” Landor.
  3. 3.
    Clearness; freedom from ambiguity; lucidity.(Law)
Phrases & compounds
Of a certainty — certainly.