A plug that can be inserted into its socket in either orientation. Reversible plugs have a "symmetric pinout," which means the contacts are duplicated on both sides.
The Two Majors
Reversible Type A USB Cable
Apple's Lightning and USB Type C are the latest reversible connectors for mobile devices. Type C was designed to obsolete Micro USB and Mini USB. See Lightning connector
and USB Type C
Introduced in 2015, TYLT's FLYP-DUO has an ultra-thin middle layer with contacts on both sides to make a normally not-reversible Type A plug reversible.