"0" or "
Zero" is normally seen as "nothing", but "0" refers specifically to having "0" amount of something as a value, as opposed to "nothing" which refers to the non-existence of something, whether it's a quantity or not.
The symbol of "0" is resemblant of the letter "O" but taller and thinner, for this reason, when used digitally it is common for an alternate version of this symbol with a diagonal
line from bottom
left to top right of the
shape to be used, for it not to be confused with the letter "O".