The word rectifier refers to the general act of straightening. It may refer to:

• Rectifier, a device for converting alternating current to direct current
• Rectifier (neural networks), an activation function for artificial neural networks
• Rectifier, a guitar amplifier manufactured by Mesa Boogie.
• Rectifier, a weapon in the gacha game Wuthering Waves, made by Kuro Games.

• Rectification (disambiguation)
• Rectified spirit