Noun
Picatinny rail (plural Picatinny rails)
English Wikipedia has an article on:Picatinny railWikipedia
(firearms) A bracket used on some firearms in order to provide a standardized mounting platform.
It has the surface space of an average smartphone and includes a Picatinny rail for camera, laser, or other attachments. Source: Internet
Both have a Picatinny rail on the upper receiver, allowing the carry handle/rear sight assembly to be replaced with other sighting devices. Source: Internet
It is equipped with a removable carrying handle and a full length quad Picatinny rail for mounting optics and other ancillary devices. Source: Internet
M16A4 United States Marine Corps M16A4 rifle with Picatinny rail and foregrip. Source: Internet
Weapons of the Modern Marines, by Michael Green, MBI Publishing Company, 2004, page 16 It is equipped with a removable carrying handle and Picatinny rail for mounting optics and other ancillary devices. Source: Internet