To the OP, to get you started, here’s a Catholic Answer:
It is true that baptizo often means immersion. For example, the Greek version of the Old Testament tells us that Naaman, at Elisha’s direction, “went down and dipped himself [the Greek word here is baptizo] seven times in the Jordan” (2 Kgs. 5:14, Septuagint, emphasis added).
But immersion is not the only meaning of baptizo. Sometimes it just means washing up. Thus Luke 11:38 reports that, when Jesus ate at a Pharisee’s house, “[t]he Pharisee was astonished to see that he did not first wash [baptizo] before dinner.” They did not practice immersion before dinner, but, according to Mark, the Pharisees “do not eat unless they wash [nipto] their hands, observing the tradition of the elders; and when they come from the market place, they do not eat unless they wash themselves [baptizo]” (Mark 7:3–4a, emphasis added). So baptizo can mean cleansing or ritual washing as well as immersion.
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