noun
trade wind
A steady wind blowing toward the equator from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere.
貿易風は帆船時代の航海に欠かせなかった。
The trade winds were essential for navigation in the age of sail.
季節風 (monsoon) is a seasonal wind that changes direction with the seasons, while 貿易風 blows consistently year-round.
Compound of 貿易 (trade) and 風 (wind), a direct calque of English 'trade wind'.