The definition of null is a zero value, or is something that is no longer valid or relevant.
(adjective)See null in Webster's New World College Dictionary
adjective
Origin: MFr nul < L nullus, not any, none < OL *n(e) oin(o)los, not a one < ne, not (see no) + dim. of oinos < IE *oinos: see one
See null in American Heritage Dictionary 4
adjective
Origin:
Origin: French nul
Origin: , from Old French
Origin: , from Latin nūllus; see ne in Indo-European roots
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