Answer:
"mole"
Explanation:
That is the definition of mole. Mole is a unit for the measurement of how much there is of something. In other words, in SI, 1 mol of a substance contains the same number of molecules/atoms as in 12 grams of carbon 12.
(Approximately 6.28 × 10^23 --> Avogadro's constant)
For further explanation, check out Wikipedia's article here:
https://en.m.wikipedia.org/wiki/Mole_(unit)
