Definition:
The Amanar vault is named after Romanian gymnast Simona Amanar, who performed it at the 2000 Olympic Games.
It is a Yurchenko-style vault, meaning that the gymnast performs a round-off onto the board, a back handspring onto the horse, and a flip off. In the Amanar, the flip off the horse is a 2.5 twisting layout back flip.

Källa: http://gymnastics.about.com/od/glossaryofgymterms/g/Amanar.htm