>Approval / Formal Approval
>Commendation / Praise
Also, when it was first used in English, it also meant proof / conclusive proof. But this meaning is obsolete as of now.
Imprimatur is another word bearing similar meaning (a mark of formal approval) though originally the word means a license to print or publish by Roman Catholic episcopal authority.
This word is derived from Latin verb approbare, which means to prove or to approve.
Example
The company has even received the approbation of its former critics.
The plan of building bridge has the approbation of the ministry of public work