What is the meaning of the word "flush"?

Definitions:

a sudden rapid flow, as of water noun
- I heard the flush of a toilet.
cause to flow or flood with or as if with water verb
- flush the meadows
flow freely verb
- The garbage flushed down the river
glow or cause to glow with warm color or light verb
- the sky flushed with rosy splendor
in the same plane adverb
- set it flush with the top of the table
rinse, clean, or empty with a liquid verb
- flush the wound with antibiotics
squarely or solidly adverb
- I hit the jerk flush in the face.