#
Number Sign (Hash)
- Unicode
- U+0023
- Category
- Punctuation
- HTML Entity
- #
- CSS
- \0023
The number sign (#) — also called hash, pound sign in American English, and octothorpe — is two pairs of crossed lines. It stands before numbers (#1, apartment #5), and since 2007 it has marked hashtags on social networks (#travel). On phone keypads it is the "pound" or "hash" key used in voice menus. It is not the musical sharp (♯), whose vertical strokes are upright and horizontal ones slanted.
On a US keyboard # is Shift+3. On UK keyboards it has its own key next to Enter, and on a UK Mac it is Option+3. On an iPhone it is on the #+= page, on Android on the ?123 page.
On a US keyboard # is Shift+3. On UK keyboards it has its own key next to Enter, and on a UK Mac it is Option+3. On an iPhone it is on the #+= page, on Android on the ?123 page.
How to Type
- Windows
- Shift+3 (US) · # key (UK) · Alt+35
- macOS
- Shift+3 (US) · Option+3 (UK)
- Linux
- Shift+3 · Ctrl+Shift+U 23
- HTML
- #
In Programming
# starts a comment in Python, Bash, Ruby, Perl, YAML and many config files, and the #! shebang on the first line of a script picks its interpreter. In C and C++ it introduces preprocessor directives (#include, #define). In CSS it is the id selector (#header) and the prefix of hex colours (#ff0000); in URLs it opens the fragment; in Markdown one to six # make a heading.
Tags
hash
hashtag symbol
pound sign
number sign
octothorpe
alt 35
shift 3
keyboard symbol
ascii