envir

Envir is an abbreviation used in computer science and statistics to refer to an environment—the mapping of identifiers to values in the context where code is executed. In programming, an environment (also called an environment frame or scope) defines the bindings available for name resolution, and controls how variables are looked up during evaluation.

In the R programming language, envir is a common parameter name for functions such as eval, get, exists, and substitute, where envir specifies the environment in which the operation should take place. The envir object is typically an environment or an environment-like object. R's environments form a linked structure that supports lexical scoping and dynamic lookup depending on the context.

Beyond R, envir is used in documentation and code samples to denote an environment object in other languages that implement lexical scoping, including Lisp, Scheme, and Emacs Lisp; there, the term environment refers to a frame containing symbol bindings.

Environments are central to concepts such as scope, binding, and evaluation strategy. They can be global, local, or nested, and can be mutable or immutable depending on the language. In practice, envir as a variable or parameter helps functions access and manipulate the current or target environment to perform tasks like symbol resolution, evaluation, or code transformation.

Note that envir is not a universal keyword in a single language; it is a conventional name used across languages to represent an environment object. The specifics—such as how environments are created, extended, or escaped—vary by language.