Thanks to Gabriele/Mourning.
lolicore is a musical movement born in 2006 thanks to the swedish Loli Ripe, which shows its features with the "Ecce Pedo" album: a harsh and extreme sound, basically Speedcore/Noise, contrasting with high pitched female vocals that seems to be a child's voice.
And the name comes from this feature, or to put it better it derives from the union of the words "lolita" (which means little girl) and the -core suffix. Lolicore often draws inspiration from the otaku culture, in fact there are anime samples in many songs; there are also many remixes of songs which are speeded up to obtain the loli effect.
Musically there aren't real genre boundaries: from the Speedcore sound of Loli Ripe and Laser Imouto, to the Breakcore one of Lolishit and goreshit, to the Noise of Nelvoroth; lately also Trance and Cybergrind projects were born.