Kogal is a Japanese fashion culture that involves schoolgirls wearing an outfit based on Japanese school uniforms, but with very short skirts. The short skirts are worn irrespective of the season. The girls may also wear loose socks and scarves, and have dyed hair. The word "kogal" is anglicized from kogyaru, a contraction of kōkōsei gyaru. The girls refer to themselves as gyaru (gals), although this word is applied to several other fashion looks as well.
Read article on Wikipedia