Is "Achoo" A Word?

...because if it is, then my nearly 17-month-old child has finally said his first word. Prior to this monumental occassion, we had no "ma-ma" or "da-da" or even "no." Not a single syllable. (Okay, ONE syllable: "OOOOOO," as in "Oh, look what I did!") What a turkey. His comprehension is remarkable: "Put the toy in the toy box." Immediately the toy is thrown in. "Are you hungry?" a big head nod as he walks to his highchair. "I'm gonna gitcha!" And off he runs with gleeful giggles.
But now, ever since his older brothers were fake sneezing and he was laughing hysterically over and over again after each dramatic achoo, he says, "ah-ah-ah-ah.... TUUU!" Oh, and you should hear the enthusiasm and the high pitch in his voice. And the head-tilt-back-wind-up and the head-thrown-forward motions. And the dimple-encased smile - oh it would melt your heart right out of your chest.

Incidentally, "Achoo" is on the official Wikipedia's list of onomatopoeia's. Their definition clearly considers onomatopoeia's to be words. So in case you are wondering if I am officially considering this a first word (rather than an additional sound), yes. I am. It's going in his baby book tonight.

And for comparison's sake, recorded in both big brothers' baby books is a long list of words (about twenty!) they BOTH had by 18 months - and even 2 and 3-word phrases. So he has some serious catching up to do in the next several weeks. Many people have consoled me that "Einstein never spoke until he was four years old."

Perhaps we have a genius in the making.