What does infinitesimally mean?
Infinitesimally is an adverb meaning to an extremely small extent or degree. It is used when a change, difference, or effect is so slight that it may be difficult or impossible to detect with ordinary measurement. The word is especially common in scientific, technical, and formal writing, where precision matters, such as when describing a minute adjustment in an instrument or an almost imperceptible variation in a measurement. It should not be confused with infinitely, which means without limit or bound. Although infinitesimally can suggest mathematical exactness or hyperbole, it ordinarily conveys that the relevant amount is vanishingly small rather than literally without any size. The related adjective is infinitesimal.
adverbTo an extremely small extent or degree; so slightly as to be scarcely perceptible.
- To an extremely small extent or degree.
"The two measurements differed infinitesimally, but the difference was enough to affect the result."
"The needle moved infinitesimally after the adjustment."
"Only infinitesimally more heat was required to trigger the reaction."
Infinitesimally small sounds like a mathematical exaggeration, but it describes a difference so tiny that it may be practically impossible to detect.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does infinitesimally come from?
The adverb comes from the adjective infinitesimal, which was formed in the 17th century from the Latin infinitus, meaning endless or unlimited. The suffix -esimal was influenced by other mathematical and scientific terminology and conveys minute or exceedingly small quantity. English later converted the adjective to the adverb infinitesimally in the 19th century. The Latin root also underlies infinite, infinity, infinitely, and infinitude.
Related word forms
How infinitesimally is actually used
Commonly used in technical, scientific, and formal contexts, especially when describing differences too small to perceive or measure precisely.
Easily confused with infinitesimally
Infinitely means without any limit or bound, whereas infinitesimally means by an extremely small amount.