It's a shorten term for "Lesbian Radar", for those people who can't really tell if men are homosexual but can definitely tell when a woman is a lesbian.
Michael: "Yeah, I'd try something but she's a lesbian."
Nathan: "How could you possibly know that?"
Michael: "Believe me man, I just know, my lesbiandar is amazing."
Nathan: "How could you possibly know that?"
Michael: "Believe me man, I just know, my lesbiandar is amazing."
by WerewolfByDay March 13, 2011