refine

definition: 
Remove impurities or unwanted elements from (a substance), typically as part of an industrial process
sentence: 
Sugar was refined by boiling it in huge iron vats.
When oil is refined this reaction is used to remove unwanted alkenes.
difficulty: 
very easy
toefl frequency: 
3
toefl classification: 
adverb: 
adjective: 
adverb sentence: 
adjective sentence: 
verb: 
verb sentence: 
noun: 
refinement
noun sentence: 
These molecules are removed from our daily diets by refinement processes.