What is Linchpin?
1.
1. Literally; n., a
2. Slang; n., Any part or person that is so vital to something that if it went missing, the whole thing would fall apart.
1. You have to
pull thelinchpin to adjust thebearings .
2. Someone has to take
the snap , so thequarterback is the football offensive team's linchpin.
See