What does node eviction mean in the Oracle RAC world?

Software environment: Oracle 12c with RAC running on RHEL The question might sound rather banal, but I wasn't able to find any word on this in the Oracle documentation I read thus far. By searching the net, I came to the conclusion that node evictions usually imply a node reboot, but that doesn't always seem to be the case, some suggest node evictions without node reboots are also possible. If that is indeed the case, when will the node be rebooted and when not? If a node cannot access the minimum required number of voting disks, then that node will be evicted. Will that node always be rebooted because of this eviction? Can one configure this behavior (i.e. change from eviction with reboot to eviction without reboot)?