Sub-MOA
A rifle or load that prints groups smaller than one minute of angle, roughly one inch at one hundred yards, the common benchmark for precision.
Sub-MOA means a rifle and load combination that keeps its group inside one minute-of-angle, which works out to about one inch across at one hundred yards and scales with distance from there. It has become the everyday benchmark that buyers and builders use to separate a precision-capable setup from an ordinary one, and many makers now advertise a sub-MOA guarantee for a given number of shots.
The honest version of the claim depends on how it is measured, since a true sub-MOA result should come from a center-to-center reading over a full five-shot group rather than a cherry-picked three-shot cluster. Reaching it reliably usually takes a match-grade barrel, ammunition tuned to the rifle, and a shooter steady enough not to add error of their own.