n A means of access, often secret and unprotected, to something.
n (computing) A secret means of access to a program or system.
n (slang) The anus, generally used in reference to anal sex.
a (US|baseball) The path of a pitch which starts outside and then slides over the plate.
v To attempt to accomplish by indirect means, especially when direct means are proscribed.
v (surfing) To enter a tube by accelerating from behind; to surf into an already formed hollow wave, in contrast to the normal method of slowing to allow a surfable wave to form.