A biddie, while difficult to define accurately while avoiding confusion, is a college age female who falls under some, most, or all of these descriptions.

-often short/petite
-gullible, easily tricked
-wears spandex pants, a miniskirt barely covering the vag, or anything from American Apparel
-footwear consists of Uggs, boots with fur on them, heels, or some combination of the three
-enjoys Biddie Songs (Low by Flo Rida ft. T-pain, Shake That by Eminem ft. Nate Dogg, etc)
-at least 80% of their facebook pictures would render them unemployable if leaked
-does not remember the last weekend that did not involve a hangover
-the couches in the G street basement are equivalent to a 5-Star Resort
-dreams of being a woman from Desperate Housewives
-Smirnoff Ice = ideal pregame
-"so what's your major?" is absolutely a legit pickup line
-wakes up in weird places
-the purpose of the bathroom/kitchen sink is obviously as a courtesy for you when you get sick
-resides in the Burlington, VT area during the academic semester

an attractive young woman

biddie is a UK reference for old people.

A high maintenance girl who, though reasonably attractive, is usually meant to be a space-filler at parties and does not offer social skills or intelligence.

A girl that wears heels too high to remain coordinated and clothes so tight and/or short that she knows her goods will fall out/show but still acts like it's an accident so all the boys pay attention to her.

A slutty young women. Usually one who is physically atractive. Usually used when describing lots of girls.

A woman of greater years