The meaning of the word currently includes nonsexual unions between individuals of indeterminate gender (we refer, as above, to a “marriage” between a coach and a player in sports), or even unions between people and ideas (again, “Barack Obama’s marriage of Reason and Faith”). Reason is not a man and Faith is not a woman; the word is used, entirely correctly, in that sentence to refer to something other than “the normal union of man and woman.”
So how does your argument address this? Why is it OK for a woman to be married to her opinion, for a man to be married to his (male) coach in a nonsexual sense, or for two abstract concepts to be married to one another…
but not for Ted and Steve to be married. Because if you are arguing, on linguistic grounds, that Ted and Steve can’t be married because marriage is exclusively defined as a sexual/procreative/legal union between one man and one woman, then you must also argue that the above usages are incorrect.
And if you argued that, you’d be wrong, and thousands of writers and experts on the English language would tell you so.
That has nothing to do with anything; it’s a silly and sad argument. How does the definition of “gay” (by which I assume you mean the secondary definition also meaning “homosexual”) logically incorporate zoophilia?
Any number of ways. I like the OED, personally, so there’s:
1. The formal union of a man and a woman, by which they become husband and wife.
Which is obviously the definition you prefer. But you can’t ignore:
2. A combination of two or more elements.
Under this definition, gay marriage certainly qualifies (so do the metaphorical “marriages” I’ve described above).
But of course, this is all pedantry. Words are defined as we choose to define them, collectively. It is disingenuous to argue that anyone fails to understand the meaning of the word “marriage” if it is applied to two men or two women. I’m married (I’m a guy, married to a woman, by the way). If I run into two women in the supermarket and I tell one of them, “this is my wife; I’m married to her,” and she replies, “This is my wife; I’m married to her,” are you really trying to pretend that the definition of the word is made somehow unclear?
For myself, I like the second OED definition, above. I think it works, and it’s the motherfucking OED. So is the OED wrong, or are you?