A soprano is a female singer with a high voice. Young boys who sing, and also girls, are usually called trebles. The word “soprano” can also refer to the top line of choir music. This would be sung by sopranos or trebles. Soprano is also used as a name for high pitched instruments, such as a soprano saxophone.
In opera there are different kinds of soprano voices:
A dramatic soprano will sing big, dramatic roles such as Aida in Verdi's opera Aida.
A coloratura soprano will have a light voice which can bounce up to very high notes (the Queen of the Night in Mozart’s Magic Flute goes up to top F (2 1⁄2 octaves above middle C).
A soubrette is usually the maid or a young girl who flirts.
A lyric soprano role needs a beautiful smooth voice, e.g. Mimi in Puccini'sLa Boheme.
In the 17th and 18th centuries many of the soprano roles were written for male sopranos. Called a castrato, they were men who had their testicles removed before puberty so that their voices would remain high pitched.