Vocaloid is a singing synthesizer application software developed by the Yamaha Corporation that enables users to synthesize singing by typing in lyrics and melody.

Hatsune Miku (初音ミク?) is the first installment in the Vocaloid 2 Character Vocal Series released on August 31, 2007. The name of the title and the character of the software was chosen by combining Hatsu (初, First?), Ne (音, Sound?), and Miku (未来, Future?). The data for the voice was created by actually sampling the voice of Saki Fujita, a Japanese voice actress.

Kagamine Rin/Len (鏡音リン・レン?) is the second installment of the Vocaloid 2 Character Vocal Series. Their surname was chosen by combining Kagami (鏡, Mirror?), Ne (音, Sound?), with the first syllables of their given names a pun on "Left" and "Right".

The third installment in the character vocal series,Megurine Luka (巡音ルカ?), was released on January 30, 2009.[34] Her surname combines Meguri (巡, Circulate?) and Ne (音, Sound?).