The "double eagle" is a score of three below par on a hole in golf. To accomplish this, a golfer has to score a hole in one on a par 4 hole, or hole out in two shots on a par 5 hole.
The double eagle is an extraordinarily rare outcome. The difficulty of either hitting a tee shot on a par-4 hole directly into the hole or combining a drive and either a long iron or fairway wood approach into a finish in the hole makes this much more unusual than a hole-in-one on a par-3 hole. For example, in 2012, the PGA Tour saw 37 holes-in-one on par-3 holes during competition but only four double eagles.