The definition of a gem is a jewel, valuable stone, or something highly valued.
(noun)See gem in Webster's New World College Dictionary
noun
Origin: ME gemme < OFr < L gemma, a swelling, bud, precious stone < IE *ĝembhna < base *ĝembh-, to bite, tooth > comb
See gem in American Heritage Dictionary 4
noun
Origin:
Origin: Middle English gemme
Origin: , from Old French
Origin: , from Latin gemma; see gembh- in Indo-European roots
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