1.NounA Christian sacrament, by which one is received into a church and sometimes given a name, generally involving the candidate to be anointed with or submerged in water.
"The child’s baptism was held at the old church.; The ceremony of baptism symbolizes spiritual rebirth."
2.NounA similar ceremony of initiation, purification or naming.
3.NounThe moment at which an object is first assigned a proper name.