term:

Seal

seal n

[Old French seel, from Latin sigillum, from diminutive of signum mark, sign]
: a device (as an emblem, symbol, or word) used to identify or replace a signature and to authenticate (as at common law) written matter see also contract under seal at contract

under seal
: with an authenticating seal affixed

vt 1 : to authenticate or approve by or as if by a seal
2 : to close off (as records) from public access

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.