The original cabling standard for
Ethernet that uses
coaxial cables. The name derives from the fact that the maximum data transfer speed is
10 Mbps, it uses
baseband transmission, and the maximum length of cables is
500 meters.
10Base5 is also called thick Ethernet, ThickWire, and ThickNet.
Also see the Ethernet Designations chart in the Quick Reference section of Webopedia.