What would you count as a baby's first word?

Does it just have to be something you recognize and understand? Does it have to be something a stranger could hear and recognize? Do they have to know what it means?

I'm going a little nuts over here, since my LO said, "hungy," to ask for a bottle, but maybe nobody else would recognize that except me?

And then my LO said, "beep," and a stranger nearby asked, "Did they just say beep?" But beep doesn't really mean anything... Right?

And then just now--I swear my LO said something that had the same intonation, sounds, everything...as, "I love you." While smiling adoringly up at me. Which is definitely impossible. Definitely. But my girlfriend looked at me and asked if our LO had just said, "I love you," before I could ask her!

So I'm losing my marbles over here. What counts as a first word???