What Makes a Word a Word

A conversation between Ben and I on what is really a word...

We were talking about printing off things at the library on campus and I told him that you usetacoud print things off. He said usetacould was not a word and told me to spell it. This is our instant message conversation:

Me: usetacould
Ben: yousedtocud
*one of us closed the window and we had to sign back on
Ben: fine bye
Me: you did that
Ben: no you fif
Ben: did
Ben: fifidiidid d
Me: i fif not
Ben: thats a word to
Me: is not
Me: it has no meaning = no word
Ben: what
Ben: type it againg i scidently clllllosed ut
Me: huh?
Ben: exactaly
Me: you accidentally closed it?
Ben: no you did
Me: meanie

My whole point was that if what is said has meaning then it does not matter if it is actually a word or not. Somehow we got a little off topic.