I don't guess you are inquiring about the extinct New Zealand bird on a gunboard, so...
MOA = Minute of Angle, 1/60th of a degree.
It is a convenient measure in shooting because it is approximately one inch on the target per hundred yards of range.
So a one MOA group is one inch at a hundred yards, two inches at 200 yards, 10 inches at 1000 yards.
Most scope and target peep sight adjustments are in MOA, too.
A quarter MOA click on a scope is supposed to move the point of aim a quarter inch on the target at 100 yards, etc.
I would not casually interchange meters and yards as rantingredneck does. There is about a 9% difference which might matter at long range or on a small target.
Sorry about the Moa joke. There really was such a bird, though.