the playing or singing of notes at the same pitch by different instruments or voices

unison singing 齐唱

Here the tenors are in unison with the basses. 此处男高音与男低音齐唱。

acting or speaking together, or at the same time

"We want ice cream!" the children chanted in unison. “我们要吃冰激凌！”孩子们齐声不断喊道。