In Ethernet, there are many names, short-cuts and explanations for different functions. Discards is one of them.
Osiris, Atlas, Mercury, Osiris as a Software, Switches
What is a discard and why does this happen?
A discard is a deleted / dropped message because the receiver could not process the packet. Generally it is caused by a full memory buffer of the receiver.
It can also occur when VLANs are misconfigured; a VLAN message enters a device and the device cannot send it further, so it discards it.