What is a dig in baseball?

A "dig" or "digging one out" is an expression to describe a defensive player accepting a baseball with a motion that captures the ball very near the ground.  This kind of expression is often, though not always, used to describe a first baseman catching a ball thrown by another player that bounces before it reaches them as they hold one foot on first base.  This expression can also be used to describe another fielder, typically an infielder, to get a ball into their glove or hand that bounced near them or immediately before reaching them.