The Collaborative International Dictionary of English v.0.48:
certified \certified\ adj.
1. endorsed authoritatively as having met certain
requirements; guranteed; as, certified milk; certified
mail; a certified check. Opposite of uncertified.
[Narrower terms: certificated, credentialed, documented;
guaranteed] See also certifiable.
[WordNet 1.5]
2. legally insane according to clinical criteria.
Syn: certifiable.
[WordNet 1.5 +PJC]
3. holding appropriate documentation and officially on record
as qualified to perform a specified function or practice a
specified skill.
Syn: qualified.
[WordNet 1.5]