prime-sign
/ˈprʌɪmsʌɪn/Christian Church. Now historical
verb
[with object] To mark with the sign of the cross before baptism; to make (a person) a Christian convert or initiate.
Origin
Middle English; earliest use found in Ormulum. Probably from Anglo-Norman primseingner, primsener, primsenier, primsiner, primeseiner and Old French primsener, primseignier to mark (a person) with the sign of the cross before baptism, to make the sign of the cross over (a person); further etymology uncertain.