noun
(automotive) A hinged board or hatch at the rear of a vehicle that can be lowered for loading and unloading.
(especially British) The hinged rear door of a hatchback.
The downstream gate in the lock on a canal or river, or in an irrigation system.
(US) Ellipsis of tailgate party.
(mining) A tunnel for drawing spent air away from the working face of a mine.
verb
(automotive, intransitive, transitive) To drive dangerously close behind another vehicle.
To follow another person through access control on their access, rather than on one’s own credentials, especially when entering a door controlled by a card reader.
(finance, of a broker) To privately purchase or sell a security immediately after trading in the same security for a client.
(US, intransitive) To have a tailgate party.