Moorhen and Water hen

Moorhen noun - Black gallinule that inhabits ponds and lakes.

Water hen and moorhen are semantically related. In some cases you can use "Water hen" instead a noun "Moorhen".

Water hen noun - Any of various small aquatic birds of the genus Gallinula distinguished from rails by a frontal shield and a resemblance to domestic hens.

Moorhen and water hen are semantically related. Sometimes you can replace term "Moorhen" with "Water hen", this terms are similar.