On The Word "Baptism"

There is a popular argument in the Church of Christ against a certain instance of baptism found in the Catholic Church. The CoC believes that baptism should only be in the form of a full and complete immersion. The Catholic Church believes that while a full and complete immersion is a valid baptism (barring that they didn't already have previous valid baptism), there are other ways to have a valid baptism, such as a pouring on the head and maybe some sprinkling. So, the argument is a denotative one. Basically, they say that the word "baptism" literally means to dip or immerse, and so that must be the only way to practice baptism. 

So, grant for the sake of argument that the word does mean to fully immerse or dip. Would it follow that this is the only mode of baptism? I'm not sure on what grounds that would be. If we want to insist that we should only use words and understand them because of their etymological roots, then this is a poor principle. There are many words we use that aren't exclusive to their literal meaning. The word "knight" means servant, but we understand this could also refer to a military person or a person of high ranking. Suppose the Bible said that only a lady can be baptized. Well, the word "lady" literally means "a maker of bread", so do we say, "Well, since the word denotes a maker of bread, I guess only bakers can be baptized" or would we rather, in this hypothetical, say that while the denotation is that of bread maker or kneader, there are other non-literal or non-denotative meanings that allow for other modes or permissions of baptism? Definitely the latter. So, in the same way, while the word "baptism" may literally mean to immerse or dip, it wouldn't follow that this is the only way we must understand it. An insistence on the etymology or the denotation would have to be justified. 

But does baptism actually mean this? Well, yes, it does. This is not controversial. But what is also not controversial is that this is not the only meaning baptism has. A brief look into a lexicon will show this. Here is what one says,

Nicander says that in order to make a pickle, the vegetable should first be 'dipped'(bapto) into boiling water and then 'baptised' (baptizo) in the vinegar solution. Both verbs concern the immersing of vegetables in asolution. But the first is temporary. The second, the act of baptising the vegetable, produces a permanent change. When used in the New Testament, this word more often refers to our union and identification with Christ than to our water baptism. e.g.Mark 16:16. 'He that believes and is baptised shall be saved'. Christ is saying that mere intellectual assent is not enough. There must be a union with him, a real change, like the vegetable to the pickle! 

 So, while some form of the word (bapto) can definitely mean to immerse, to be baptized more accurately means to change form. And of course, this makes sense in light of some passages, like Matthew 3:11 which talks about the baptism of fire and baptism of the Holy Spirit. You cannot immerse yourself in fire or the holy spirit, but you can definitely be changed by it. It can make you from a sinner to someone in sanctifying grace. Since the purpose of baptism is to change you, not just merely get you wet, this use of the meaning of baptism is a better fit, and so is a better interpretation. We needn't insist on the CoC reading of baptism to mean to fully immerse and dip, and so they can't use this line to say sprinkling and pouring are invalid modes of baptism.