Most important part of something (8)
I believe the answer is:
mainstay
(Other definitions for mainstay that I've seen before include "chief supporter" , "Pillar of strength" , "big support" , "Strongest support" , "Most important support" .)
I believe the answer is:
mainstay
(Other definitions for mainstay that I've seen before include "chief supporter" , "Pillar of strength" , "big support" , "Strongest support" , "Most important support" .)