The term “Zombies” in the comics.

I started reading TWD comics. I’m currently in Volume 3 where they meet the prisoners. They have said the word Zombie twice before this part, I figured it was an accident, but this time it’s different. Rick literally says, we call them zombies. The big prisoner says zombies twice. I really doesn’t seem like you can make the same mistake three times in a row. I’m just scratching my head because I thought the author said the word “Zombie” doesn’t exist in TWD.

Besides the point, I’m enjoying the comic!