by lil blam loc February 29, 2008
Super Dimension Fortress, a public access free unix system which started as an Apple BBS in 1981. Today they use alpha servers running UNIX. www.freeshell.org
I have an SDF account.
by UnixFrker February 24, 2005
Super Dimension Fortress, the classification of the ship from the seminal, famous 1980s Japanese anime "Macross." In America, in the anime's "Robotech" adaptation, the acronym was changed to "Super Dimensional Fortress," and the Macross was referred to as "The SDF" frequently.
by Moggraider January 16, 2008
Stands for the Sick depressed feeling you get when you see a person/couple who are so beautiful and you know they will never be yours/you will never be in such a painfully beautiful relationship that you just have to sit on your bed and cry.
omg the guy in this film is so hot, why is my boyfriend not that beautiful and sentimental? I have sdf :(
by *gsedj* December 17, 2012