Real Dictionary

rail
If you travel or send something by rail, you travel or send it on a train.
Rails are the steel bars which trains run on.
countable noun: A rail is a horizontal bar attached to posts or fixed round the edge of something as a fence or support.
countable noun: A rail is a horizontal bar that you hang things on.
verb: If you rail against something, you criticize it loudly and angrily.

rail in American English 1
a bar of wood, metal, etc. placed horizontally between upright posts to serve as a barrier or support
noun: a bar of wood or metal fixed horizontally for any of various purposes, as for a support, barrier, fence, or railing
transitive verb: to furnish or enclose with a rail or rails

rail in American English 2
to speak bitterly or reproachfully; complain violently
intransitive verb: to utter bitter complaint or vehement denunciation
transitive verb: to bring, force, etc., by railing

rail in American English 3
any of a number of gruiform marsh birds (family Rallidae), characterized by short wings and tail, long toes, and a harsh cry
noun: any of numerous birds of the family Rallidae, that have short wings, a narrow body, long toes, and a harsh cry and inhabit grasslands, forests, and marshes in most parts of the world

rail in British English 1
noun: a horizontal bar of wood, metal, etc, supported by vertical posts, functioning as a fence, barrier, handrail, etc

rail in British English 2
verb: to complain bitterly or vehemently

rail in British English 3
noun: any of various small wading birds of the genus Rallus and related genera: family Rallidae, order Gruiformes (cranes, etc). They have short wings, long legs, and dark plumage