Here are definitions to some of the more ambiguous genre labels or those with Japanese terms:

Chibi - Anime title which include reoccurring characters drawn in the “chibi” style, ie. super deformed style with small bodies and large heads. (”Chibi” is Japanese for dwarf or small)

Children’s Show - Anime by nature is targeted towards younger viewers, but this genre label refers to titles who are targeted to children in grade school or younger. They could, but not always, be educational in nature.

Ecchi - Anime titles with great deal of fanservice, generally has girls in suggestive positions and skimpy clothing. If you see panty shots, then it can probably be considered ecchi. (Ecchi is Japanese for pervert)

Dogfights - Not actual dogs fighting, but the aerial military term referring to combat between opposing flying machines.

Gender Switch - Anime title in which main character(s) are ‘transformed’ to the opposing gender or are cross-dressing.

Goth-Loli - see Gothic Lolita

H-game Origins - H-games or eroge games are generally ‘adult visual novel’ PC games that are quite popular amongst otaku in Japan. They are commonly dating sim games with fanservice and special rewards such as nude or sex scenes with anime girls. A good amount of harem genre anime titles are based on H-games.

Harem - where the main character, usually male, has multiple romantic interests who compete for his affection.

Live Action – technically not an animation title because it uses real actors and sets, but is based on an originally anime or manga title.

Reference Heavy - Anime titles which involve a great deal of otaku-ish terms and often refers to other anime and/or manga in its episodes.

Serious - Anime titles that tries to make its themes or characters as realistic as possible. These shows typically deal with more heavy topics such as suicide, child abuse, etc or more adult topics such as politics, careers, etc.

Shojo - Anime title aimed at a primarily young female audience.

Shounen - Anime title aimed at a primarily young male audience.

Slapstick - a sub-genre of Comedy in which physical violence and exaggerated reactions are often used as sources of comedy.

Space - as in outer space

Tsundere - Anime title in which one or more main characters possess strong Tsundere traits. See Tsundere

Yaoi - a Japanese term refering to manga or anime which contain male homosexual themes. Yaoi typically refers to titles with sexually explicit material while Shounen-Ai (Boy Love) refers to those that do not. I decided to lump both under the Yaoi genre label for simplicity’s sake. Yaoi titles are generally targeted towards women.

Yuri - a Japanese term refering to manga or anime which contain female homosexual themes. Yuri typically refers to titles with sexually explicit material while Shojo-Ai (Girl Love) refers to those that do not. I decided to lump both under the Yuri genre label for simplicity’s sake. Yuri titles are generally targeted towards men.