The symbol # is known variously in English-speaking regions as the number sign, hash, octothorpe, or pound sign. Various other characters have a similar shape, including:
- # (number sign), ＃ (fullwidth), ﹟ (small)
- ♯ (U+266F) musical sharp sign
- ⌗ (U+2317) Viewdata square
- ⵌ (U+2D4C) Tifinagh letter Tuareg yazh
- ⧣ (U+29E3) equals sign and slanted parallel
- 井 (U+4E95) CJK unified ideograph-4E95
