1. a sudden backward rush or surge of water, air, or other material
Usage: often used in contexts involving waves, explosions, or fluid dynamics

Examples

• The backrush of water from the breaking wave knocked the surfer off his board.
• The explosion created a powerful backrush of hot air through the corridor.
• Swimmers need to be aware of the backrush when large waves recede from the shore.
• The backrush of the tide pulled debris back into the ocean.