"Marriage", to me, has a very specific connotation. It means man/woman, bride/groom, husband/wife, etc.
There is nothing religious about that.
There is absolutely no reason why that connotation HAS to change to appease a group of people.
I've stated way back in the beginning of this thread that I'm all for civil unions with all the same legal benefits as marriage. But just don't call it marriage, because it's not.
Just because something doesn't fit a definition means that you have to change the definition until it does fit. That's just stupid.