# What is the term for whatever is being differentiated?

When we integrate a function:

$\int^b_a {2\over x^2} dx$

The expression to be integrated (is this case ${2\over x^2}$) is referred to as the integrand.

When we differentiate a function:

${d \over dx } {2 \over x^2}$

Is there a word to describe the expression to to be differentiated? For instance, if I wanted to say "In the above equation, two over x squared is the --------", what would I fill in the blank?

• Given function?? Commented Jan 29, 2014 at 20:51
• Clearly, it's the differentiand. Though, strangely, Google doesn't recognize this term. Commented Jan 29, 2014 at 20:54
• Follow-up question: is there any reason why you would need such a term? I don't think "integrand" is used beyond calculus either.
– Lost
Commented Jan 29, 2014 at 22:45
• @Lost I'm writing a program where I have a higher-order function that accepts another function as input and differentiates it, and I'm looking for something to name the argument. Commented Jan 29, 2014 at 23:10
• @ValekHalfHeart Fair enough. As others have said, there doesn't seem to be a commonly used term, so anything is fair game.
– Lost
Commented Jan 29, 2014 at 23:13