'Bishoujo' simply means "pretty girl" in Japanese.
A bishoujo series, however, is a more loaded term. They are Fan Service series aimed towards male audiences. These series will use highly attractive female characters (often of The Beautiful Elite variety, although this is not necessary) up to about twenty-five years old whenever possible. This is especially noticeable in a series where male characters and older women make unusually few to no appearances, even if the story's setting and premise would suggest otherwise.
Lately, among fans, it often takes a self-derogatory tone. Many bishoujo series blatantly appeal to male audiences with pandering tropes, causing large amounts of Selective Squick and Values Dissonance that help cement the Otaku stereotype. Adding a guy to the mix ironically just gets it labeled as a Harem Genre story.
When a series of this kind does attract Fangirls, the series often loses this term. Compare and contrast Shoujo Demographic and Magical Girl, in which there are cute girls, but the target audience is female. Also contrast Puni Plush, Gonk, Hunk, Bishonen.
This is an East Asian media only trope. Please do not put Western examples here.
- Pretty much every girl in Elfen Lied, Diclonius and human alike, is very beautiful. Because of this, the opening scene is particularly memorable, what with Lucy going on a killing spree while wearing nothing but a mask.
- Gunslinger Girl has an especially jarring dichotomy between the age of the girls in question and their occupation.
- Naturally sent up in Excel Saga, which featured a Bishoujo episode in which the art became noticeably more shiny and all of the male regulars except Pedro were deliberately excluded. Pedro's Big No comes when the male cast finally comes to exact punishment for his appearance—and we still don't get a good look at any of them.
- Azumanga Daioh - although it is expressly not a Harem Series, but rather a Schoolgirl Series; the only regular male characters are a creepy, middle-aged teacher with a fetish for high school girls and a giant floating orange cat that may or may not be Chiyo's father. Plus, you know, that one schoolboy who fixes Yukari's bike and is then thrown into the series whenever they need to show another student aside from the main cast? Yeah, we're talking about him.
- Galaxy Angel is a bishoujo series; the Galaxy Angel gameverse has the same characters as a Harem Genre, but the anime removes the central male.
- Soukou no Strain.
- Aria, where only beautiful young girls appear to be allowed to steer sight-seeing gondolas.
- Koihime Musou is notable for its sheer volume of bishoujo. There are literally dozens of all shapes and sizes.
- Similar to Strawberry Panic, everyone in Mariasama ga Miteru is insanely beautiful, including the regular passerby - too bad if you're male though.
- Tenshi ni Narumon.
- To LOVE-Ru.
- Reimei no Arcana.
- Fruits Basket with it's beautiful people has many bishoujo.
- Rumble Roses.
- Dead or Alive Beach Volleyball, complete with revolutionary Jiggle Physics.
- Final Fantasy X-2.
- Arcana Heart.
- Vanguard Princess.
- Tokidensho Angel Eyes.
- Hyperdimension Neptunia and its sequel is nothing but this.
- Getter Love!!
- Touhou. An astounding grand total of two males appear in the official works, and one of them is a magical cloud. The females? About 60+ of them, not counting pre-Windows versions.
- Katawa Shoujo. A Visual Novel made by an international team in the style of Japanese Dating Sims.