- Aeronautics. the airstream pushed back by a revolving aircraft propeller. Compare backwash (def 2), wash (def 31).
- the airstream generating reduced air pressure and forward suction directly behind a rapidly moving vehicle.
"In fact Rincewind was already half a mile out over the dark sea, squatting on the carpet like an angry buddha, his mind a soup of rage, humiliation and fury, with a side order of outrage...
"He reached up and touched his hat for reassurance, even as it lost its last few sequins in the slipstream."
- Terry Pratchett, Sourcery