0 is a number and, more technically, the digit that represents that number numerically. It holds a central role in mathematics, holding many algebraic structures.
The word zero in English language comes from French zéro which comes from Italian zero. The first use of zero in English was in 1598.
Leonardo Fibonacci (dated 1170–1250), an Italian mathematician who grew up in North Africa is the one who have introduced the decimal system in Europe along with the concept of void, for which he used the term zephyrum.
The word zero is a transliteration of the arabic word sifr, which means void. The symbol 0 was born while counting with stones on sand: when the last stone was taken away there was nothing anymore on the sand, except for a circular imprint.
Mathematically zero is an even number (divisible by 2 with no remainder), it is also the smallest non-negative integer and the only natural number not to be positive (nor negative).
The number is of course used to express a quantity, in this usage it is correct to identify it with nothingness. Although, a set with zero elements is empty but is still a set: when the score of a match is 0-0 it means that none of the teams has scored. The match has been played though and we can’t say that “nothing” happened. It is not convenient to perfectly identify the number zero with the theorical concepts of nothingness and void.
Zero is also used to number the Tarot card of The Fool, alongside with number twenty-two.