The portion of a communications link used for the transmission of signals from an Earth terminal to a satellite or to an airborne platform. An uplink is the converse of a downlink. An uplink or downlink is distinguished from reverse link or forward link.
(by analogy, less formally) The communication path from a mobile device to a base station, a consumer to the network backbone, a client device to a server etc.
Data transmission from a data station to the headend.