to give assurance; testify; vouch for the validity of something (usually followed by to).
Origin: 1300–50; Middle English certifien < Middle French certifier < Late Latin certificāre, equivalent to Latin certi- (combining form of certus decided; see certain) + -ficāre-fy
Related forms
cer·ti·fi·er, noun
pre·cer·ti·fy, verb (used with object), -fied, -fy·ing.
re·cer·ti·fy, verb (used with object), -fied, -fy·ing.