as in vs foremost

as in

• In the sense of. 

• Used other than figuratively or idiomatically: see as, in. 

foremost

• Most importantly. 

• In front, prominently forward. 

• First in time. 

• Positioned in front of (all) others in space, most forward. 

• Coming before (all) others in time. 

• Closest to the bow. 

• Of the highest rank or position; of the greatest importance; of the highest priority.