Read the dictionary definition of sink. All definitions for this word.
1. a covered cistern; waste water and sewage flow into it
2. plumbing fixture consisting of a water basin fixed to a wall or floor and having a drainpipe
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. (technology) a process that acts to absorb or remove energy or a substance from a system
1. the ocean is a sink for carbon dioxide
5. fall heavily or suddenly; decline markedly
1. The real estate market fell off
6. embed deeply
1. She sank her fingers into the soft sand
2. He buried his head in her lap
7. descend into or as if into some soft substance or place
1. He sank into bed
2. She subsided into the chair
8. pass into a specified state or condition
1. He sank into nirvana
9. fall or descend to a lower place or level
1. He sank to his knees
10. cause to sink
1. The Japanese sank American ships in Pearl Harbor
11. fall or sink heavily
1. He slumped onto the couch
2. My spirits sank
12. go under
1. The raft sank and its occupants drowned
13. appear to move downward
1. The sun dipped below the horizon
2. The setting sun sank below the tree line