The highest male voice; in speaking and singing, countertenors have the normal range of a tenor, but are able, by singing in falsetto, to go higher, into the contralto
range, and, with the great ones, into the soprano
They are usually assigned roles written originally for the castratos
, yanking those roles away from the contraltos.
Is that a female alto singing...? It sounds different... it's probably a countertenor.