Ethernet CSMA-CD

Ethernet is a multi-access technology that is designed to deal with Network Collisions. Collisions are situations where two or more hosts attempt to send data at the same time on the same medium resulting in corruption of data.

Carrier Sense Multiple Access/Collision Detection or CSMA/CD is a mechanism used by Ethernet to minimize collisions on the shared medium, and to deal with collisions when they do occur.

https://networklessons.com/cisco/ccna-200-301/introduction-to-ethernet#Duplex