A unicast could be a message being sent to a single goal. So what is unicast flooding then? When a switch gets a outline ordained to a have in which it does not have in it's CAM table at that point the switch will surge the unicast outline to all ports with the same VLAN ID. Basically, the unicast becomes a broadcast.

The term for this is often unknown unicast flooding. In the illustration underneath, let's expect Have A sends a frame to the switch ordained to Have B. Since have B isn't within the CAM table, the switch will surge the unicast outline to all ports with the same VLAN ID.

Usually what the CAM table looks like for the switch as Have A sends it's frame:
https://mobileinfoworld.com/?p=552