0 present participle of sift
1 to put flour, sugar, etc. through a sieve (= wire net shaped like a bowl) to break up large pieces:
2 to make a close examination of all the parts of something in order to find something or to separate what is useful from what is not:
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.