The "E" Word?

Student: "Teacher!  Teacher! Stan just said the "E" word."
Me:  "D"?
Student:  "NO! E!"  Writes an e on a piece of paper and looks at me like I am a total idiot.

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Any ideas what the "E" word might be?  l called the student over and he admitted he said something he shouldn't have and he knows that the "E" word is real bad.  He promised not to say it again, so I guess that's good!

Oh 3rd grade!