Double birdie is a term used in golf to describe scoring two strokes under par on a single hole. The term is a shorthand used by golfers to signal their achievement to their playing partners or to spectators. However, there are several synonyms for the term double birdie, including eagle, green eagle, and albatross. These terms are used to describe more exceptional scoring achievements. An eagle is scoring two strokes under par, a green eagle is three strokes under par, and an albatross is four strokes under par. These alternative terms are used to describe a golfer's impressive performance on a particular hole and can signify a significant achievement in the game of golf.