Actually, it's the only thing he came to after being home with me for 2 weeks. I tried several names and he just ignored all of them.

One night, I was watching Star Trek: Voyager and some one said "Seven of Nine" and his ears shot up. It took me a little while to figure out what he was reacting to and finally, I walked out of the room and said "Seven" and he came to me.

That's pretty much how he got his name.