Include

Include means to contain as a component of a larger whole or to bring something into a group or list. It is used to indicate that a person, item, or feature is part of a package, plan, or set, such as “The price includes tax” or “The tour includes a visit to the museum.” In everyday use it often pairs with “in” or “as” to specify what is part of the whole.

Originating from Latin includere, from in- “in” and includere “to enclose,” the word has retained this sense of enclosing or surrounding something within a larger unit. Usage tends to emphasize integration or addition rather than mere possession.

In mathematics, inclusion expresses a subset relation: A is included in B if every element of A is also an element of B. This is written A ⊆ B, with the related concept of a proper subset A ⊂ B when A is strictly smaller. The inclusion map i: A → B illustrates the idea by embedding each element of A into B.

In computing, include refers to directives or functions that insert the contents of one file into another. In C and C++, the preprocessor directive #include brings code from a header or source file into the current file. Other languages offer similar facilities, such as PHP’s include() and require() functions. Inclusion supports code reuse and modular design but can introduce dependencies and potential circular references if not managed carefully.