This is the 4391st most frequent Polish word.
ilość
"Quantity" or "amount."
Here, 'ilość' ('number') is used to describe a countable quantity ('books').
Mam dużą ilość książek.
I have a large number of books.
In this case, 'ilość' ('amount') references an uncountable quantity ('sugar').
Ilość cukru w tej herbatce jest za duża.
The amount of sugar in this tea is too high.
'Ilość' ('number') is used again, now for a countable noun ('people'), emphasizing measurement.