(Ephesians 4:4-6) There is one body, and one Spirit, even as ye are called in one hope of your calling; One Lord, one faith, one baptism, One God and Father of all, who is above all, and through all, and in you all.
There is only "one baptism" worthy of important mention:
(Mark 1:8) I baptize you with water, but he will baptize you with the Holy Spirit.
The baptism of the Holy Spirit.
I baptize my french fries with ketchup all the time. Yet, ketchup is no more part of the definition of the word 'baptize' than water is. We're talking about an action here, no? I believe that it would be a critical mistake to assume 'water' into the definition of the word "baptize" when ever it is used.
To "baptize" means to be "placed into", or "immersed", or it can mean 'dipped into'. We are "placed into" the Body of Christ when we receive the indwelling of the Holy Spirit, which is the one true baptism. As a result of that, we have become "immersed" with Christ Jesus, being one with Him, actually being "in Christ". The Holy Spirit is the agent of that baptism, not water. That baptism is always the result of faith. And Jesus is always the Baptiser.
There is a baptism that saves, not water baptism, but a genuine faith which will result in a clear conscience, through the resurrection of Jesus Christ. 1 Peter 3:21 (paraphrased by me for clarity). Pictured just before that in that same scripture is the water, which is God's judgment, and the ark, which pictures Jesus Christ. In the ark, they were saved from God's judgment, the water. In Christ, likewise.
Gal. 3:26 - 27 For you are all sons of God through faith in Christ Jesus. For as many of you as were baptized into Christ have put on Christ.
1 Cor. 12:13 For by one Spirit we were all baptized into one body ... and have all been made to drink into one Spirit.
Understanding this, we can then correctly understand what the word "baptism", or "baptize" means in other passages that speak of the same resurrection, and the same life transforming experience (born again), such as Romans 6:3-11; Colossians 2:10-14, and we can then know that these passages are speaking of our Spirit baptism, which is always the result of our initial, God given faith.
The types never save, but always point. The one true "placing into", the one true "immersion"? It's the Spirit baptism.