Noun

1. Plumbing fixture consisting of a water basin fixed to a wall or floor and having a drainpipe
2. (technology) a process that acts to absorb or remove energy or a substance from a system
3. A depression in the ground communicating with a subterranean passage (especially in limestone) and formed by solution or by collapse of a cavern roof
4. A covered cistern; waste water and sewage flow into it

Verb

1. Fall or descend to a lower place or level
2. Cause to sink
3. Pass into a specified state or condition
4. Go under,
5. Descend into or as if into some soft substance or place
6. Appear to move downward
7. Fall heavily or suddenly; decline markedly
8. Fall or sink heavily
9. Embed deeply