baptism

Greek baptisma (baptism) derives from baptizein (to immerse) — the two terms describe the same act, immersion being the physical reality of which baptism is the theological name.

Baptism is the New Covenant initiation rite — as circumcision was the sign of the Abrahamic covenant, baptism is the sign of the New Covenant (Colossians 2:11-12).

Greek baptizein (to immerse) is the NT term for the immersion ritual — baptismal immersion is not a different act but the same act named literally. Tevilah (Jewish) and ghusl (Islamic) immersion are cross-traditional cognates of the same act.