The quality or state of being indubitable.
Something that cannot be doubted; a certainty.
The state of being valid, authentic or genuine.
The genuinity - as distinguished from the efficacity or the regularity - of a sacrament as a result of some formal dispositions being fulfilled.
State of having legal force.
A quality of a measurement indicating the degree to which the measure reflects the underlying construct, that is, whether it measures what it purports to measure (see reliability).