A soprano is a singer with a voice range (using scientific pitch notation, where middle C = C4) from approximately (C4) to "high A" (A5) in choral music, or to "soprano C" (C6, two octaves above middle C) or higher in operatic music. In four part chorale style harmony the soprano takes the highest part which usually encompasses the melody. For other styles of singing see Voice classification in non-classical music.
Typically, the term "soprano" refers to female singers but at times the term male soprano has been used by men who sing in the soprano vocal range using falsetto vocal production instead of the modal voice. This practice is most commonly found in the context of choral music in England. However, these men are more commonly referred to as countertenors or sopranists. It should be noted that the practice of referring to countertenors as "male sopranos" is somewhat controversial within vocal pedagogical circles as these men do not produce sound in the same physiological way that female sopranos do. The singer Michael Maniaci is the only known man who can refer to himself as a true male soprano because he is able to sing in the soprano vocal range using the modal voice like a woman would. He is able to do this because his larynx never fully developed like a man's voice does during puberty.
In choral music the term soprano refers to a vocal part or line and not a voice type. Male singers whose voices have not yet changed and are singing the soprano line are technically known as "trebles". The term "boy soprano" is often used as well, but this is just a colloquialism and not the correct term.