Just think 1"@ 100 yards is close enough. Here's a U-Tube deal that will help you.
Understanding Minute of Angle (MOA) - Rifle Shooting Technique - NSSF Shooting Sportscast - YouTube
I see "MOA" used to describe firearm accuracy quite a bit, mostly from manufacturers. I searched and can't find what it stands for.
Minute of Arc (arcminute) or Minute of Angle (some even refer to it as minute of "accuracy" but that is a more slang term in the gun world, and technically inaccurate)
while a very technical term the following is an introductory explanation
The arcminute is commonly found in the firearms industry and literature, particularly concerning the accuracy of rifles, though the industry tends to refer to it as minute of angle. It is especially popular with shooters familiar with the Imperial measurement system because 1 MOA subtends approximately one inch at 100 yards, a traditional distance on target ranges. Since most modern rifle scopes are adjustable in half (1⁄2), quarter (1⁄4), or eighth (1⁄8) MOA increments, also known as clicks, this makes zeroing and adjustments much easier. For example, if the point of impact is 3" high and 1.5" left of the point of aim at 100 yards, the scope needs to be adjusted 3 MOA down, and 1.5 MOA right. Such adjustments are trivial when the scope's adjustment dials have an MOA scale printed on them, and even figuring the right number of clicks is relatively easy on scopes that click in fractions of MOA.
so.. Imagine a circle bisecting your body, think about how a circle has 360 degrees... now think of every one of those degree's having 60 minutes within them.
ONE minute of one degree is One inch at 100 yards. multiply that One inch by 60 and you have (obviously) 60 inches, or one degree of a full circle with a radius of 100 yards, diameter of 200 yards and a circumference of (approx) 628 yards.
now if you go and check the math one degree of 60 inches multiplied by 360 and divided by 12 (for feet) and 3 (for yards) comes to 600. one minute at 100 yards is an approximation and when you multiply one by 60 by 360 the relatively minute difference ultimately becomes 28 yards.
as you can tell it's a very deep subject in firearms, however generally applied to Rifles. This, however, is handgun forums and therefor MOA does not compute...
most pistols would (exaggerating slightly) be measured in degrees of angle, not minutes at 100 yards, lol.