Baptism, from Greek βαπτίζω (baptízô), is a religious act of purification by water usually associated with admission to membership or fullness of membership of Christianity.

The Greek-English Lexicon of Liddell and Scott gives the primary meaning of the word βαπτίζω, from which the English word baptism is derived, as dip, plunge, but indicates, citing Luke 11:38, that it was used also to mean perform ablutions.[1]

By analogy, the English word "baptism" is used of any ceremony, trial, or experience by which one is initiated, purified, or given a name.[2] See Other initiation ceremonies below.

The periodically repeated Jewish purification rite of mikvah is not normally spoken of as baptism, largely because of the Christian associations of the word "baptism".