To make (something) perpetual; to make (something) continue for an indefinite time; also, to preserve (something) from extinction or oblivion.
To prolong the existence of (something) by repetition; to reinforce.
To record (the testimony of a witness) which may be lost before a matter comes to trial.
Perpetual, or made perpetual; continued for an indefinite time.
To keep safe; to defend; to guard; to prevent harm coming to.
To book a passenger on a later flight if there is a chance they will not be able to board their earlier reserved flight.