A few years ago was
The 5-year-old brother was invaded by mathematical terminology from the parents of math tutors who worked at home. And my mom with a sense of humor trolled the students when they stopped:
The derivative sinus?
"Cosinus," replied her 5-year-old spank with a stunned voice.
And the derivative cosinus?
and minus sinus.
Unfortunately, the faces of the poor students could not be photographed at the time.