Etymology: derived from "lolicon", derived from Vladimir Nabokov's novel "Lolita", titled after an effectionate nickname that the novel's protagonist Humbert Humbert had for his "nymphet" Dolores Haze, who died at the end of the novel at nineteen years old.
"Loli" refers to erotica of fictionaly drawn girls 12 years and younger, or who look like they are: girls who are either mid-pubescent or pre-pubescent: teen or preteen.
- - -
Dolores was portrayed by Dominique Swain (born 1980) in the 1997 film adaptation of the Lolita so she would've been approximately sixteen when it was filmed, for comparison.
Kubrick's 1962 version used actress Sue Lyon (born 1946) who would've also been approximately sixteen.
- - -
The name's use in Japan becomes apparent in the 1980s during two distinct OVA series both sharing the title "Lolita Anime" or ロリータアニメ
Wonder Kids released a 6-part series which is alternatively known as "Wonder Magazine Series" from 21 February 1984 – 25 May 1985. The first five episodes are 30 minutes long while the 6th is an hour.
Nikkatsu released a trilogy from 15 December 1984 – 10 January 1985 starring a girl named Aki.
- - -
Some adolescent-excludes have over time, without precedent, pushed to exclude mid-pubescent teen girls from the term, which is controversial and there is not a consensus to do so.