Translation guide
A barrier built across a river to hold back water. In Japanese, the most common word is ダム, a loanword from English. There is also a native Japanese word 堰 (せき), which often refers to a smaller weir or barrier, not necessarily a large dam. For large hydroelectric or flood-control dams, ダム is standard.
dam (large structure)
dam (small weir)
Often for traditional or agricultural barriers.
The learner wants to refer to a large structure that blocks a river to create a reservoir, generate electricity, or prevent flooding.
The standard word for a large dam, used in most contexts including hydroelectric dams, flood control dams, and reservoirs.
This dam was built to prevent floods.
The water level in the dam is getting low.
A native Japanese word for a barrier across a river, but often refers to a smaller weir or sluice gate rather than a massive dam. Can be used for traditional irrigation structures.
The learner wants to refer to a small dam-like structure, often for irrigation or controlling water flow in a small river.
The most natural word for a small weir or barrier, especially in traditional or agricultural contexts.
This weir is said to date back to the Edo period.
A more specific term for an irrigation weir, often used in historical or technical contexts.
The learner wants to refer to a dam built by beavers.
The straightforward way to say 'beaver dam'. ビーバー is the loanword for beaver.
I found a beaver dam in the river.
ダム is a modern loanword used for large-scale dams like hydroelectric dams. 堰 (せき) is a native word for smaller barriers, often used for irrigation or controlling water flow in smaller rivers. Using ダム for a small weir might sound odd, and using 堰 for a massive dam is uncommon.
Kurobe Dam is a famous dam in Japan.
This weir is for agricultural water.
川に堰を作って水を田んぼに引いた。
They built a weir in the river to draw water into the rice paddies.
古い井堰がまだ使われている。
The old irrigation weir is still in use.