Refers to a standard (IEEE 802.3) of the LAN networking system.

Ethernet was first developed by Xerox and patented in 1975. To this day it remains the most commonly used wired LAN technology.

The Ethernet family of technologies include:

10BASE5 (also known as ThickNet)
- The original Ethernet standard which used a single coaxial cable to transfer up to 10Mbit/sec. The 5 in the name refers to the maximum segment length of 500 metres.
10BASE2 (also known as ThinNet)
- This standard used a thinner coaxial cable than its 10BASE5 counterpart and was very common at one time. It could transfer 10Mbit/sec but had a shorter segment length than 10BASE5, although the 2 in its name suggests a 200 metre segment length, it was actually decreased to 185 metres. Each machine connected to the coaxial cable by means of a T-adaptor, and the ends of the cables required a terminating device.
10BASE-T
- This standard was the first to use twisted pair cabling, hence the T in the standard's name. It provided 10Mbit/sec transferred over two twisted pair cables, it used either a hub or a switch to network the devices, similar to the configurations in use today.
100BASE-T (Fast Ethernet)
- This describes up to 3 different standards, namely, 100BASE-TX, 100BASE-T4 and 100BASE-T2. It provides up to 100Mbit/sec over twisted pair cabling, with each standard using a different category of cable. 100BASE-TX, the most dominant standard in use today, uses two pairs of a Category-5 cable. 100BASE-T4 uses all 4 pairs of a Category-3 cable, and is limited to half-duplex mode. 100BASE-T2, although it never had any devices manufactured to support it, utilised two pairs of Category-3 cable and provided full-duplex support.
Gigabit Ethernet
- 1000BASE-T (IEEE 802.3ab) - Provides 1000Mbit/sec over twisted pair Category 5, or Category 5e (recommended) copper cables.
- 1000BASE-SX - Provides 1000Mbit/sec over short-range multi-mode fiber cables.
- 1000BASE-LX - Provides 1000Mbit/sec over long-range single-mode fiber cables.
- 1000BASE-CX - Provides 1000Mbit/sec over copper cables but limited to 25 metres (now obsolete).
10 Gigabit Ethernet (10GE / 10GbE / 10 GigE)
- This standard provides 10Gbit/sec data transfer using either single-mode fibre (long haul), multi-mode fibre (up to 300 metres), copper backplane (up to 1 metre) and copper twisted pair (up to 100 metres).
40 Gigabit Ethernet (40GbE)
- Currently still in development. Scheduled for June 2010.
100 Gigabit Ethernet 100GbE
- Currently still in development. Scheduled for June 2010.