From Latin extensive, extension is the action and effect of extending or spreading (make something take up more space, spread or spill what is next, unfold, unwrap). The term can be used to name the measure of space that occupies a body and the ability to occupy a part of the space.

For instance: “I think this table is longer than ours”, “It is a large tunnel that reaches the center of the mountain”, “I want you to write a short report with the explanations of the case”, “The editor asked me to be careful with the length of the notes as there is little space available”.


The extension of a cable facilitates the connection and allows the mobility of the artifacts.

An electrical cord as an extension

The extension of an electric cableOn the other hand, it is another cable that is added to the main one to facilitate the connection of an electrical installation.

An extension allows the mobility of an electrical appliance, since it can be moved away from the socket: “Please, find an extension so we take the fan to the patio that is very hot”, “I need an extension for the nightstand: I can’t read in bed in the dark”.

The concept in music

Music is another of the areas that does not escape the use of the term that we are dealing with now. In his case, it is used to refer to the interval that exists in a musical instrument between what would be its highest sound and its lowest sound.

However, it is also true that that same word and that meaning can also be applied to what would be the voice of a singer. In this way, you will be able to know perfectly what your vocal capacity is and the range of possibilities that it offers you.


For anatomy, extension is the opposite of flexion.

Extension in anatomy and in the field

In anatomy, extension is the movement of the body parts in an anteroposterior direction. The concept is opposed to the notion of flexion: “The coach asked me to do extension exercises to gain plasticity”.

Likewise, within the anatomical sphere, we cannot ignore the existence of what is known as the extension reflex, which is nothing more than an automatic and involuntary response where tendons and bones take center stage.

Within the agricultural and livestock field, mention must be made of what is known as agrarian extension. Under this name is an action that basically consists of applying the whole set of new knowledge, technology and new discoveries, the result of research, to what would be the exploitation that works with animals or to which it is dedicated to the cultivation of certain plants for food.

The notion in Cuba and in computing

Another different use of this term that concerns us is the one given in Cuba, for example. Specifically, in this country what is done is to use the expression extension chair. With it, what he tries to define is what is commonly known as a lounger.

The computing uses the concept of extension to refer to the character string that is appended to the name of a file, usually after a period, and that allows to identify the type of file for its correct execution: “I need a program that allows me to open documents with a RAR extension”.