fwy. is the written short form of freeway, the American word for a wide, fast road between cities, with no traffic lights. You see it on maps, in addresses, and in directions: Harbor Fwy, I-5 Fwy. The full stop marks it as an abbreviation on the page; big road signs often drop the stop and just say FWY. This is American writing. In Britain the usual word is motorway; in Taiwan we just say 高速公路. Though actually, Americans also mix freeway, highway, and expressway in daily talk, and some freeways now have a toll — the name stayed even when the road is not free. Do not use fwy. in a school essay; write the full word, or say highway / freeway in running English.