A countertenor is a man trained to sing very high — as high as many women altos, sometimes higher — in church music, opera, and old European song. The sound is often a trained falsetto, though actually some singers use more of their chest voice than people think. It is a specialist word. You meet it on concert programmes, not in pop charts. He is not 'a tenor who is against something', and he is not a boy, and he is not the old cruel castrato of history, though those voices lived in a similar high range. The name comes from a voice part that sat against the tenor line. Younger pop fans may never need the word; choir and classical students will.

假聲男高音