Finite and infinite sets
A finite set is a set with a finite (limited) number of elements.
The set of the letters in the English alphabet is finite. There are 26 elements (the letters) in the alphabet.
The set of the natural numbers smaller than 10 is finite.
The set of all human beings is finite.
If the number of elements in a set is infinite, we have an infinite set.
The set of the natural numbers is infinite.
The set of the integers smaller than 10 is infinite: it consists of 9, 8, ..., 0, -1, -2, ...
The set of all possible words (whether they mean anything or not) is infinite.