Definition of tailgates:
(n) :
(automotive) A hinged board or hatch at the rear of a vehicle that can be lowered for loading and unloading.
(v) :
(automotive, intransitive, transitive) To drive dangerously close behind another vehicle.
(v) :
(US, intransitive) To have a tailgate party.
(n) :
(especially British) The hinged rear door of a hatchback.
(v) :
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.
(n) :
The downstream gate in the lock on a canal or river, or in an irrigation system.