MILF n. (mIlf)
A primarily American slang acronym standing for "Mother I'd Like to Fuck". The term MILF (or less commonly 'milf') is used most frequently by adolescent males to refer to attractive older women. Some define a MILF as a woman at least old enough to be ones own mother while others consider it simply to be a woman who is a mother. Some notable women labeled as MILFs include Angelina Jolie, Mary-Louise Parker, and most recently Sarah Palin.
The first definitive use of the word MILF was in the 1999 film American Pie though it is likely it was in colloquial use prior to the release of the movie. Regardless of its origin, the word quickly became adopted into pop culture and spawned entire businesses: type MILF into any internet search engine today and a remarkable number of porn sites are brought up. The acronym has also influenced the creation of several similar terms including GILF (grandmother), SILF (sister), BILF (babysitter), and TILF (teacher).