"act or ceremony of baptizing," c. 1300, verbal noun from christen (v.). Old English had cristnung.
Entries linking to christening
christen v.
c. 1200, "to baptize into the Christian church," from Old English cristnian "to baptize," literally "to make Christian," from cristen "Christian" (see Christian). Especially to baptize and name as an infant, hence "give a name to at baptism" (mid-15c.) and the general sense of "give a name to" anything, without reference to baptism (1530s). Related: Christened; christening.