rail

noun

1. a bar of wood, metal, etc. placed horizontally between upright posts to serve as a barrier or support
2. a fence or railing; specif., the fence surrounding the infield of a racetrack
3. any of a series of parallel metal bars laid upon crossties or in the ground to make a track for railroad cars, streetcars, etc.
4. a railroad or railway as a means of transportation: to travel by rail
5. a horizontal piece of wood separating the panels in doors or wainscoting
6. the rim of a billiard table
7. Naut. a narrow, wooden or metal piece forming the top of a ship's bulwarks

transitive verb

adjective

intransitive verb

noun pl. rails or rail