noun
water well
A hole dug or drilled in the ground to access underground water. Used in everyday contexts.
昔はこの村の人はみんな井戸の水を使っていた。
In the old days, everyone in this village used water from the well.
庭に古い井戸がある。
There is an old well in the garden.
井 (い) is a more formal or literary term for a well, often used in compound words or classical contexts, while 井戸 is the common everyday word.
Compound of 井 (い, 'well') and 戸 (と, 'door'), referring to the wooden frame or lid often placed over a well. The reading いど is a regular sound change from いと.