Baptō (βάπτω) means "to dip, plunge into a liquid, to immerse briefly, to dye." It is the root of baptizō (G907) but has a more limited and literal sense. In the NT it appears in Luke 16:24 (Lazarus dipping his finger in water), John 13:26 (Jesus dipping the bread), and Revelation 19:13 (Christ's robe dipped in blood).
The three NT uses of baptō span the mundane and the majestic. In Luke 16:24, the rich man begs Lazarus to baptō his finger in water — a small mercy in agony, contrasted with the great mercy he refused during his lifetime. In John 13:26, Jesus dips the psōmion (bread morsel) and gives it to Judas — a final act of grace to the betrayer. In Revelation 19:13, Christ's robe is dipped in blood — the blood of His enemies (Isaiah 63:3) or His own blood (atonement). The word that began with a finger in water ends with the conquering King whose robe tells the story of history.