A slab is a FUCKING HUGE American car from the late '60s-late '80s like a 66 Impala, 70 Cutlass, 77 Eldo, 82 Fleetwood, 88 Grand Marquis etc. Just a giant "slab" of metal on which you can floss your Vogues or Triple Gold Daytons. Probably the finest examples are late '70s Lacs.