- any of the nearly constant easterly winds that dominate most of the tropics and subtropics throughout the world, blowing mainly from the northeast in the Northern Hemisphere, and from the southeast in the Southern Hemisphere.
- any wind that blows in one regular course, or continually in the same direction.
- a wind blowing obliquely towards the equator either from the northeast in the N hemisphere or the southeast in the S hemisphere, approximately between latitudes 30° N and S, forming part of the planetary wind system
