revivor1
/rɪˈvʌɪvə/noun
A person who or thing which revives, renews, or restores something; a reviver.
Origin
Mid 16th century; earliest use found in Robert Barnes (c1495–1540), religious reformer. From revive + -or.
revivor2
/rɪˈvʌɪvə/noun
Law. The process of reviving a suit or action which has been rendered void, especially by the death of one of the parties; an instance of this. Usually in bill of revivor. Now chiefly US.
Origin
Early 17th century (in an earlier sense). Apparently alteration of reviver (although this is first attested slightly later). For a similar phenomenon, compare some forms retainer.