The term "falsetto" is a Latin derivative meaning "false voice" and stems from Italian culture of the Middle Ages. Music scholars and speech pathologists use the term "head voice" interchangeably with falsetto.
The term "head voice" refers to the process of bringing the vocal ability out of the chest and lungs, and into the singer's head. This process allows a singer to go beyond his normal ability and range of singing.
Some scholars believe achieving a falsetto register in singing cannot be achieved by female singers. Speech pathologists and visible evidence through filmed experiments reject this notion. But falsetto singing is most recognizable in male singers because of the difference in frequency ranges between male and female singers.
There are many types of falsetto singing, and the practice transcends musical genres but can be identified most blatantly in operatic singing and more recently in metal. Metal singers use falsetto to demonstrate their vocal range and give the performance a feeling of a melancholic Gothic opera.
Famous falsetto singers are Rob Halford of Judas Priest, Freddie Mercury of Queen and Roger Hodgson of Supertramp.