Bracketin

Bracketin is a term used to describe a style of notation in which items, phrases, or data are enclosed within various types of brackets to indicate structure, optionality, or placeholders. It is not a formally standardized concept and appears mainly in informal computing, data annotation, and online communication.

Etymology and usage: The term combines 'bracket' with the suffix '-in' to suggest an ongoing process. It emerged in online communities and hobbyist documentation where flexible notation was valued for rapid prototyping and readability.

Notation conventions: Different brackets convey different semantics. Parentheses () commonly group elements; square brackets [] denote optional content or inserted material; braces {} can indicate sets or alternatives; angle brackets <> can mark placeholders or tags. In some contexts, double brackets [[ ]] or [[...]] are used to indicate editorial notes or nested insertions.

Examples: The descriptor for an API endpoint might be written as /api/resource/[version]/<id> where [version] is optional and <id> is a required placeholder. In a data template, you might see {field} indicating a variable and [default] indicating an optional default value.

Relation to other concepts: Bracketin overlaps with bracketing and bracket notation in mathematics and computing but remains distinct as a loose label used by certain communities for flexible, human-readable notation.