sinkhole

1. A hole formed in soluble rock by the action of water, serving to conduct surface water to an underground passage.
2. A depressed area in which waste or drainage collects.
3. A hole in the playfield that rewards the player when the ball is guided into it.
4. A domain name server that has been configured to hand out non-routeable addresses for all domains, so that every computer that uses it will fail to get access to the real website.
5. An attack which redirects requests, whether network or memory accesses, to a new location defined by the attacker.

Plural sinkholes