Defined as per IEEE Standard 802.3. Variant of Ethernet that uses Thicknet coaxial cables.

10 stand for transmission speed in Mega bits per second. 10Mbps.

Base stands for Baseband signal technology.

Cable type: Thick Coaxial cable (yellow color) with extra braided shielding, 50-ohm resistance.  Also called Thicknet. 10BASE5 uses cable type RG(Radio Guide)-8U (U means General Utility Use).    

Cable width: 1cm approx.

Connectors used:

Vampire Tap - A vampire tap (also called a piercing tap fitted with Transceiver) is a device for physically connecting a station, typically a computer, to a network that uses 10BASE5 cabling. This device clamps onto and "bites" into the cable (hence the vampire name), inserting a probe through a hole drilled using a special tool through the outer shielding to contact the inner conductor, while other spikes bite into the outer conductor. The vampire tap usually has an integrated AUI (Attachment Unit Interface), from this a short multicore cable connects to the network card in the station.

Vampire tap types : With or without N Connector.

N Connector - similar to BNC connector used to join/extend coax cables(through Vampire cap). 

Transceiver:  Also called Media Attachment Units (MAU). The help converting the primitive signals from the AUI interface to what’s required on the physical media, as well as performing collision detection. Recommended at every 2.5 to 3 meters.

Length: Maximum supported length is 500metres (1600 ft). The numeral 5 in 10Base5 is taken from this (Length 500meters)

Topology type: Bus Topology. 100 nodes can be connected using 10Base5 coaxial cable in a bus topology.