infinitesimal

nouns

(mathematics) a variable that has zero as its limit
infinitesimal
domain category
a science (or group of related sciences) dealing with the logic of quantity and shape and arrangement
math, mathematics, maths
is a type of (narrower)
a quantity that can assume any of a set of values
variable, variable quantity

adjectives

infinitely or immeasurably small
"two minute whiplike threads of protoplasm"; "reduced to a microscopic scale"
infinitesimal, minute