The definition of foremost is something most important, highest ranking or most relevant.
(adjective)The most important reason behind a decision is an example of the foremost reason.
See foremost in Webster's New World College Dictionary
adjective
Origin: ME foremeste < OE formest (akin to OFris formest, Goth frumists), superl. of OE forma, itself a superl. of fore (see fore); later understood and spelled as fore + most
adverb
See foremost in American Heritage Dictionary 4
adjective
Origin:
Origin: Alteration of Middle English formest, first
Origin: , from Old English; see per1 in Indo-European roots
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