Status is a category of attack, along with Physical and Special, which was introduced in Generation IV. Moves in this category can increase/decrease Pokémon stats and cause status problems.
Categories
Statistics
Moves of these sorts such as Growth and Leer bring positive and negative effects on Pokémon.
Protection
There are moves that completely protect Pokémon from incoming attacks of all kinds, however, moves such as Feint, Shadow Force, and Phantom Force can render protection moves useless. Multiple usage of protection moves can result in the chance of them succeeding very unlikely.
Status Effects
There are moves that bring status effects on Pokémon such as burns, paralysis, poisoning, sleep, etc.
Terrains
Introduced in Generation VI are terrain moves that can that temporarily change the battlefield to the playing Pokémon's advantage. All the terrain moves increase the Pokémon of the same type's power by 50% while each also have different secondary effects. So far, only three terrain moves have been introduced so far.