1) to set a seal upon, mark with a seal, to seal
    1a) for security: from Satan
    1b) since things sealed up are concealed (as the contents of a
        letter), to hide, keep in silence, keep secret
    1c) in order to mark a person or a thing
        1c1) to set a mark upon by the impress of a seal or a stamp
        1c2) angels are said to be sealed by God
    1d) in order to prove, confirm, or attest a thing
        1d1) to confirm authenticate, place beyond doubt
             1d1a) of a written document
             1d1b) to prove one's testimony to a person that he is what
                   he professes to be