A score of two strokes under par on a single golf hole is called an eagle.
The name describes a score two below the hole’s expected number of strokes. On a par-three hole, an eagle is achieved with one stroke, commonly called a hole-in-one. On a par-four, it takes two strokes; on a par-five, it takes three. Eagles are therefore possible on several hole types, not just par-fives.
An eagle is better than a birdie, which is one stroke under par, but not as rare as an albatross, or three strokes under par. A score equal to par is simply a par, while one stroke over par is a bogey. These terms describe performance relative to the hole’s par, not a fixed number of shots.
The golfing use of “eagle” developed after “birdie” became established as a term for an exceptional score. The larger bird represented an achievement better than a birdie. On a scorecard, an eagle is commonly marked with a circle around the score.