Notary
/ˈnəʊtəri/
Definition 1 of 1
Pro Tip 1/3Legal Authenticity
Notaries ensure that important documents are authentic and can be trusted legally. 
I met with a notary to verify my identity on the power of attorney.
Pro Tip 2/3Witnessing Signatures
A notary is often required to watch someone sign a document to confirm it's their genuine signature. 
Before mailing your affidavit, let a notary witness your signature.
Pro Tip 3/3Official Seals
Notaries use a special seal or stamp to show they've checked a document. 
The notary affixed her official seal after witnessing the signing of the contract.