The discussion about spelling and pi have inspired me to think about some of the taboo words in math.
One of the "taboo" words in math is the word "cancels." I usually tell my student to stay away from this word if possible becuase of its misuse.
The biggest misuse I see with students is the student does a problem similar to
x - and states that the x's cancel. I think this is clearly wrong. x
However If a student is doing a problem such a + b = a + x and states by the addition (or subtraction) property of equality, the a's cancel, I feel this is clear way of describing their work. If the variables don't cancel in a - a, what do they do?