In simple terms it is not much else, though it is a broad, generic term. Ethernet is a standard communications protocol embedded in software and hardware devices, intended for building a local area network (LAN).
By means of the software, cables and a networking switch, data and resources (computers, printers, scanners, etc.) can be shared among a number of users.
Basic Ethernet principles have existed for, probably, 20 years or more. However more recent developments encompass wireless technology (e.g. “Blue Tooth”) and other facilities allowing devices to be connected over wide distances (to create a Wide Area Network – a WAN).