A fact is an element of truth expressible as a proposition.

Among the familiar ideas of logic in which the element of Secondness is predominant, may be mentioned, in the first place, the conception of a fact. The easiest definition of a Fact is that it is an abstract element of the real, corresponding to a proposition. But this needlessly introduces the element of Thirdness; but it can be prescinded from it. … A Fact may be defined as the Secondness which consists between anything and a possibility, or Firstness, realized in that thing.