Vocaloid is a music genre where voice is synthesized with a software.
It’s named so because of the Vocaloid software, made by Yamaha, which synthesizes singing voices.
Hatsune Miku
Hatsune Miku, Wikipedia - Hatsune Miku is a character for a voice bank for Vocaloid, released in 2007.
She is very popular, people go to her concerts, there are a lot of fan stuff with her - figures, posters, t-shirts, you name it. She’s not the only one or first virtual voice characters, by the way. MEIKO, for example, was released three years before Miku.
MEIKO
Links
- Vocaloid famdom wiki. Most probably the only resource you need to dive into the world of vocaloid program and music created with it.