extends

Extends is the third-person singular present form of extend. It also appears as a keyword in several programming languages to indicate inheritance or subtype relationships, and as a directive in stylesheet languages.

In object-oriented programming, extends denotes that one entity derives from another. In Java, class Car extends Vehicle indicates that Car inherits fields and methods from Vehicle; Java uses the implements keyword for interfaces. In TypeScript and ES6 JavaScript, class Dog extends Animal creates a subclass; TypeScript also uses extends in generic constraints, such as function wrap<T extends Animal>(t: T). In Scala, classes extend a superclass or trait, and can mix in additional traits using with. Some languages (notably Kotlin) use different syntax, such as a colon, to express inheritance.

In CSS preprocessors like Sass and SCSS, the @extend directive allows one selector to reuse the style rules of another selector, enabling inheritance of styles without duplicating declarations.

In English usage, extends is the present tense form of extend, as in "The peninsula extends into the sea." It conveys lengthening or broadening of scope, range, or influence.