# Different terminology for discrete vs. continuous “marginal” concepts?

e.g. Marginal Utility.

If the good you're consuming is discrete, like "slices of pizza eaten", then authors (or at least the author of my textbook) talk about Marginal Utility at each quantity eaten as "the amount of extra utility you get from eating 'one more' slice".

If the good you're consuming is continuous, like "amount of juice drunk", then if you did that you'd just always get "an infinitesimal amount of extra utility, from 'the next' infinitesimally small sip". That's useless, so instead you use derivatives and ask what the instantaneous rate of change in utility is, with respect to juice.

Though related, these are different quantities, and they have different units ("difference in height" vs. "slope" of the total utility curve).

Do they also have different names?