Be at ease and Sit-down

Sit-down and be at ease are semantically related. In some cases you can replace phrase "Sit-down" with "Be at ease", this phrases are similar.

Sit-down noun - A strike in which workers refuse to leave the workplace until a settlement is reached.

Be at ease and sit-down are semantically related. Sometimes you can use "Be at ease" instead a verb phrase "Sit-down".