:

Colon

ASCII Code: 58•Category: punctuation

The colon (:) serves as a versatile punctuation mark that introduces lists, explanations, and time notation while playing crucial roles in programming syntax and data formatting.

Technical Details

ASCII Code
58
HTML Entity
:
Hexadecimal
0x3A
Binary
00111010
Octal
72

Usage & Examples

Programming

char symbol = ':'; // ASCII 58

HTML/Web

: or :

Common Uses

colonpunctuationliststimeratiosprogrammingexplanation

How to Type This Character

Windows

Alt Code:
Hold Alt and type58 on numeric keypad
Character Map:
Search "Character Map" in Start menu

Mac

Character Viewer:
Press Ctrl +Cmd +Space
Copy & Paste:
Easiest method - copy from this page!

💡 Pro tip: The fastest way is to bookmark this page or copy the character from our ASCII library!

Related Characters

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"
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'
Single quote
#39
,
Comma
#44
-
Hyphen
#45
.
Period Dot
#46
;
Semicolon
#59
?
Question mark
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«
Left Guillemet Double Angle Quotes
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»
Right Guillemet Double Angle Quotes
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¿
Inverted Question Mark
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#
Hash symbol
#35

About the Colon

Structural Organization

The colon creates logical relationships in text by introducing explanations, lists, quotations, and examples. It signals that what follows will elaborate on or specify what precedes it, making complex information more digestible and organized.

Time And Measurement

Universal standard for time notation (hours:minutes:seconds) and ratio expressions (3:1, 16:9). The colon enables precise temporal and proportional communication across cultures and technical fields, from schedules to mathematical expressions.

Programming Syntax

Essential in programming for dictionary definitions, case labels, inheritance notation, and type annotations. The colon structures code logic and data relationships in languages like Python, JSON, CSS, and many others.

Digital Formatting

Critical for URL schemes (https:), metadata labels, and structured data formats. The colon enables consistent data organization in web protocols, file systems, and database schemas.

History of the Colon

200 BCE

Ancient Greek Rhetoric

Greek grammarians used dots and marks to indicate pauses in oratory, laying groundwork for punctuation systems that would eventually include the colon for longer pauses and explanations.

1500s

Renaissance Printing

Italian and French printers developed the modern colon (:) as two dots stacked vertically, standardizing its appearance and establishing its role in formal written communication.

1600s

English Grammar

English writers adopted the colon for introducing lists and explanations, codifying its grammatical functions that remain standard in modern English writing and education.

1784

Time Notation

Standardized time notation began using colons to separate hours, minutes, and seconds, establishing the universal temporal format used globally in digital clocks and schedules.

1970s

Programming Languages

Early programming languages adopted colons for syntax structure, creating conventions for code organization that continue in modern languages like Python, JavaScript, and CSS.

Cultural Impact

The colon evolved from ancient rhetorical pauses to become fundamental to modern information organization, enabling clear communication in everything from literature to digital interfaces.

Usage Examples

Lists and Explanations

Example
Meeting agenda: 1) Budget review 2) Project updates 3) Next steps

Introducing itemized lists and detailed explanations

Time Notation

Example
Meeting time: 2:30 PM, Duration: 1:45:30 (hours:minutes:seconds)

Universal time formatting and duration expression

Programming Syntax

Example
Python: if condition: | CSS: color: blue; | JSON: {'name': 'value'}

Code structure and data formatting across languages

Ratios and Proportions

Example
Screen ratio: 16:9, Mix ratio: 3:1 water to concentrate

Mathematical and technical proportion notation

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