# infinitesimal

in·​fin·​i·​tes·​i·​mal | \ (ˌ)in-ˌfi-nə-ˈte-sə-məl , -zə-məl\

## Definition of infinitesimal

(Entry 1 of 2)

1 : immeasurably or incalculably small an infinitesimal difference
2 : taking on values arbitrarily close to but greater than zero

infinitesimal

noun

Definition of infinitesimal (Entry 2 of 2)

: an infinitesimal quantity or variable

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## Other Words from infinitesimal

infinitesimally \ (ˌ)in-​ˌfi-​nə-​ˈte-​sə-​mə-​lē , -​zə-​mə-​ \ adverb

## What is the origin of infinitesimal?

Noun

Infinite, as you probably know, means "endless" or "extending indefinitely." It is ultimately from Latin infinitus, the opposite of finitus, meaning "finite." The notion of smallness in infinitesimal derives from the mathematical concept that a quantity can be divided endlessly; no matter how small, it can be subdivided into yet smaller fractions, or "infinitesimals." The concept was still in its infancy in 1710 when Irish philosopher George Berkeley observed that some people "assert there are infinitesimals of infinitesimals of infinitesimals, etc., without ever coming to an end." He used the adjective in a mathematical sense, too, referring to "infinitesimal parts of finite lines." Less than a quarter century later, the adjective had acquired a general sense applicable to anything too small to be measured.

## Examples of infinitesimal in a Sentence

an infinitesimal moment in time a soft drink with only an infinitesimal amount of caffeine

Recent Examples on the Web: Adjective

There has been some debate in the comments section regarding an answer given by Michael, who treated the multidimensional figure purely mathematically and came up with an answer of less than 50 percent for a small, but not infinitesimal, change. Instead, there were centuries of infinitesimal changes. Meanwhile, paid family leave for many American workers is infinitesimal or nonexistent, meaning that for those who do need to take care of a family member, there’s often no choice but to quit work. The odds of otherwise healthy people facing hospitalization is even lower than this infinitesimal amount. The good news, if there is any, is that Windows Mobile market share was always tiny to begin with, and now is largely infinitesimal: 0.10 percent, according to NetMarketShare. The reality, however, is that planning the coming summit meeting between President Trump and Kim Jong-un to discuss North Korea’s nuclear future will require deciding countless, infinitesimal details, often via tricky diplomatic negotiations. Still, by the five-year mark, the fish had almost died off in the lake — near-extinction of a species due to an infinitesimal amount of a hormone. And the marginal cost of overpaying is infinitesimal relative to that base.

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'infinitesimal.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

## First Known Use of infinitesimal

1710, in the meaning defined at sense 2

Noun

1706, in the meaning defined above

## History and Etymology for infinitesimal

borrowed from New Latin infīnītēsimālis, from infīnītēsimus "infinite in rank" (from Latin infīnītus "having no limit, infinite entry 1" + -ēsimus, suffix of higher ordinal numbers) + Latin -ālis -al entry 1 — more at vigesimal

Noun

New Latin infīnītēsimus "infinite in rank" + -al entry 2 — more at infinitesimal entry 1

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## Statistics for infinitesimal

Last Updated

30 Jun 2019

Look-up Popularity

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## The first known use of infinitesimal was in 1706

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More Definitions for infinitesimal

infinitesimal

## English Language Learners Definition of infinitesimal

: extremely small

infinitesimal

in·​fin·​i·​tes·​i·​mal | \ in-ˌfi-nə-ˈte-sə-məl \

## Kids Definition of infinitesimal

: extremely small The chance of winning is infinitesimal.

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More from Merriam-Webster on infinitesimal

Spanish Central: Translation of infinitesimal

What made you want to look up infinitesimal? Please tell us where you read or heard it (including the quote, if possible).

#### hapless

having no luck

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