Active player

From MTG Salvation Wiki

The active player is the player currently taking his or her turn. (Compare with all other players in the game, who are nonactive players.) When more than one player have to take actions or make choices, usually the active player goes first (see APNAP).

From the Comprehensive Rules 102.1. A player is one of the people in the game. The active player is the player whose turn it is. The other players are nonactive players.