1. The principle or quality of being determined by extension (physical size, scope, or range) rather than by intention or meaning; in logic and philosophy, the view that the truth value or identity of expressions depends only on their extension (the set of objects they refer to) rather than their intension (their meaning or definition).
Usage: formal; philosophy and logic

Examples

• In formal logic, extensionality allows two predicates with the same extension to be treated as equivalent.
• The principle of extensionality in set theory states that two sets are equal if they have the same members.
• Philosophers debate whether natural language exhibits extensionality or intensionality in its semantics.
• Extensionality simplifies logical systems by focusing on what terms refer to rather than how they are described.
• The extensionality of mathematical functions depends on their domain and range rather than their symbolic representation.