Asterisk Key Explained — Functions on Keyboards & PhonesThe asterisk key (*) is small, understated, and found on nearly every keyboard and phone. Despite its modest appearance, it performs a wide range of functions across computing platforms, telephony, writing, and even mathematics. This article explores the asterisk key’s history, placements, primary uses, platform-specific functions, accessibility roles, and practical tips for power users.
Brief history and symbol overview
The asterisk (from Greek asteriskos, meaning “little star”) has been used in writing since antiquity as a typographic mark to indicate omissions, corrections, or footnotes. On modern devices it appears as the asterisk character “*” and is typically pronounced “asterisk” in English and “star” in many telephony contexts. Its star-like shape makes it intuitive for marking special or wildcard meanings.
Physical placement and variations
- On full-size computer keyboards the asterisk is produced with Shift+8 on US layouts (the same key as the number 8). On numeric keypads the key often shows an asterisk by itself.
- On many laptop compact layouts it’s still Shift+8; some international layouts may place it elsewhere or use different input methods.
- On telephones (landline and mobile), the asterisk is a dedicated key, usually located at the bottom-left of the dial pad (below 7 and left of 0). It’s commonly labelled “*” or “star.”
Common uses on keyboards
- Wildcard and search: In many search engines, file systems, and programming contexts, the asterisk acts as a wildcard, representing any number of characters (e.g., *.txt matches all text files).
- Multiplication: In programming and plain-text math, * denotes multiplication (e.g., 6 * 7 = 42).
- Pointers and dereferencing: In languages like C and C++, * is used for pointers (declaration and dereference).
- Repetition operators: In regular expressions, * means “zero or more” of the preceding token (e.g., a* matches “”, “a”, “aa”, …).
- Emphasis in plain text/Markdown: Single or double asterisks are used for italic or bold in formats like Markdown (e.g., italic, bold).
- Footnotes and editorial marks: In written text, * can mark footnotes or indicate corrections/omissions.
- Keyboard shortcuts: Some software assigns the asterisk to specific functions—examples include expanding tree views in file managers or spreadsheet-specific operations.
Uses on numeric keypads and calculators
- On calculators and numeric keypads, * is the standard multiplication key.
- On some systems, the numeric keypad asterisk also functions as a modifier (e.g., some remote-control protocols use it as a “menu” or special function key).
Telephony functions
- Menu navigation: Many automated phone systems use the asterisk to navigate menus, return to previous menus, or cancel actions.
- Special dialing codes: On landline and mobile networks, star codes (also called vertical service codes) begin or end with * to access carrier features (e.g., *67 to block caller ID in some countries). Star codes differ by carrier and country.
- Voicemail and call-management: * often serves as a “back” or “cancel” button within voicemail systems.
- Conference calls and PBX systems: * can trigger host commands (mute/unmute, record) depending on system configuration.
Platform-specific examples
- Windows: In File Explorer, typing *.docx in the search box finds Word files; numeric keypad * may expand all folders in some tree views.
- macOS: Asterisk is accessible via Shift+8; Spotlight and Finder searches can use wildcards in some contexts.
- Linux/Unix shells: Shell globbing uses * as a wildcard; regular expressions use it for repetition.
- Programming: In Python, * is used for multiplication, argument unpacking (*args), and keyword unpacking (**kwargs uses two asterisks). In C/C++, * handles pointers.
- Mobile phones: Long-pressing the asterisk key on some phones toggles input modes or inserts special characters.
Accessibility and assistive uses
- Screen readers: The asterisk character is read as “asterisk” or “star” depending on context; it’s often used as a marker for required form fields (e.g., an asterisk next to a field label).
- Shortcut alternatives: For users with motor impairments, remapping the asterisk function (e.g., for multiplication) to larger on-screen buttons can improve usability.
Tips, tricks, and troubleshooting
- Need a literal asterisk in shells? Quote or escape it (e.g., ‘*’ or *) to prevent wildcard expansion.
- Searching file systems: Combine * with other wildcards (e.g., data_*.csv) to target ranges.
- Regular expression caution: Remember that * is a quantifier and should be paired with a token (e.g., .* to match any sequence). Use non-greedy forms when necessary (e.g., .*?).
- Phone menus: If * doesn’t behave as expected, check country/carrier-specific star codes or consult the system’s menu prompt.
Quick reference — common meanings
- Wildcard in searches and file globs
- Multiplication operator in code/calculators
- Repetition quantifier in regular expressions
- Pointer/dereference operator in C/C++
- Menu/navigation key in telephony
- Footnote/annotation marker in text
The asterisk key is a compact, multipurpose tool bridging text, code, and telephony. Whether you’re searching files with *.pdf, writing regular expressions, or navigating an automated phone tree, the asterisk’s star-shaped promise is the same: shorthand for “something special.”