Greek: Bapto, to dip. Consists of the process of immersion, submersion and emergence. Used in the dyeing of a garment, or the drawing of water by dipping one vessel into another. To whelm, cover wholly with a fluid. Baptizo, to make whelmed, fully wet.
English: Latin and Greek baptisma, from Greek, bapto, I dip in water. The initiatory sacrament of the Christian religion; the dipping among water; or sprinkling with water.
Water Baptism is the most persecuted truth in the two thousand years history of the Christian Church.
It's central truth. as in the Greek definition above, is Death, Burial and Resurrection.