The Use of "large" and "big"

large: We usually use large to describe greater than average size, quantity or amount; something is significant . For instance, we would say had a "large" role in the conference.



big: Big is ususally used to imply to all types of things which are measuring by a size. For instance, we would say big effort and big project
Sometimes big can also mean
Mature or grown-up: big enough to take the bus by herself.
Older or eldest. Used especially of a sibling: My big brother is leaving for college next week.



reference: http://llrc.eng.ntnu.edu.tw/English/search/default.htm