Diameter is probably correct in your case but Ø is often used to distinguish zero form O. I have also seen it used for the greek letter phi on occasion.

The standard way of telling a letter O from a number 0 in handwriting is to put a slash through the number.

The symbol that looks like a 0 with a line through it is the greek letter “theta”: θ. It is just a variable, you could as easily just call it x instead. For exponents, we usually type ^ (carat) in front. it is sin2θ. So 1 – cos2θ = sin2θ.

The distinction came into prominence on modern character displays. The digit 0 with a dot in the centre seems to have originated as an option on IBM 3270 displays. , or “∅” (Unicode character U+2205), representing the empty set, as well as to the letter Ø used in several Scandinavian languages.

Ø (or minuscule: ø) is a letter used in the Danish, Norwegian, Faroese, and Southern Sami languages. Though not its native name, among English-speaking typographers the symbol may be called a “slashed O” or “o with stroke”.

The letter “Ø” is sometimes used in mathematics as a replacement for the symbol “∅” (Unicode character U+2205), referring to the empty set as established by Bourbaki, and sometimes in linguistics as a replacement for same symbol used to represent a zero. Slashed zero is an alternate glyph for the zero character.

Here’s how to make a slashed zero:

1. Click the cursor where you want the slashed zero to appear.
2. Press Ctrl+F9. You’ll see brackets appear.
3. Type the following (or copy and paste it from this post): eq o (0,/)
4. Press Shift+F9. The code should resolve itself into a slashed zero.

Press and hold the Alt key, then type 0216 on the numeric keypad on the keyboard’s right. Remove your finger from the Alt key. Immediately you remove your finger from the Alt key, the diameter symbol will show.

The number ‘zero’ is shaped more like an oval while the letter ‘o’ is shaped like a circle. Maybe if you look at them more closely, you can tell the difference. Here you go! 0-zero. O-letter. 0O → See! The second one is the letter and the first one is the number. The number is thinner than the letter.

In the standard horizontal number line, the zero is called the origin. Points to the right of the origin are positive numbers, and points to the left are negative numbers. Any number plotted on the line is called a coordinate.

0 is neither positive nor negative. By most definitions 0 is a natural number, and then the only natural number not to be positive. Zero is a number which quantifies a count or an amount of null size. In most cultures, 0 was identified before the idea of negative things, or quantities less than zero, was accepted.

Definition of zero. (Entry 1 of 3) 1a : the arithmetical symbol 0 or 0̸ denoting the absence of all magnitude or quantity. b : additive identity specifically : the number between the set of all negative numbers and the set of all positive numbers.