What does inextensible mean?
Inextensible means unable to be extended or made longer. The word is especially common in technical writing, where an inextensible string, cable, chain, or other idealized object may change its shape or direction but not its length. It is more precise than the informal phrase “cannot be stretched,” because it identifies a defining physical or structural limitation. The adjective is relatively uncommon in everyday speech but useful in engineering, physics, materials science, and formal description. When describing real substances, context may be important: many materials are described as inextensible under specified conditions even though they can deform slightly in practice. The negative prefix in- joins the Latin-derived adjective extensible, emphasizing the absence of the capacity to extend.
adjectiveNot capable of being extended, stretched, or elongated. It is used especially in technical and formal contexts to describe materials, objects, or geometric forms that cannot be lengthened.
- Unable to be extended, stretched, or made longer in length.
"The engineers used an inextensible cable to hold the load in place."
"The garment is made from a lightweight but inextensible fabric."
"In the model, the cable is treated as perfectly inextensible under tension."
An inextensible string can change shape, but not length—a distinction that turns everyday language into precise mechanics.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does inextensible come from?
Inextensible was formed in the 19th century from the negative prefix in- and the Latin-derived adjective extensible. The underlying root is Latin extendere, meaning “to stretch out” or “to extend,” which also gave rise to words such as extent, extension, and extensive. The prefixed form entered English in technical writing, where it became especially useful for describing idealized objects that can bend but cannot lengthen.
Related word forms
How inextensible is actually used
This is a relatively uncommon formal and technical term. In physics, it may describe an idealized object whose length cannot change, even though real materials can usually stretch to some degree.