What is the meaning of the word "refine"?

Definitions:

attenuate or reduce in vigor, strength, or validity by polishing or purifying verb
- many valuable nutrients are refined out of the foods in our modern diet
improve or perfect by pruning or polishing verb
- refine one's style of writing
make more complex, intricate, or richer verb
- refine a design or pattern
make more precise or increase the discriminatory powers of verb
- refine a method of analysis
treat or prepare so as to put in a usable condition verb
- refine paper stock