- strong, generally westerly winds concentrated in a relatively narrow and shallow stream in the upper troposphere of the earth.
- similar strong winds in the atmosphere of another planet: jet streams on Jupiter.
- the exhaust of a jet or rocket engine.
- a narrow belt of high-altitude winds (about 12 000 metres high) moving east at high speeds and having an important effect on frontogenesis
- the jet of exhaust gases produced by a gas turbine, rocket motor, etc
