1 : taking on values arbitrarily close to but greater than zero
2 : immeasurably or incalculably small
Did You Know?
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.
Stella includes a lottery ticket in every birthday card she sends despite the infinitesimal chances that it will be a winning one.
"Across the nation, voters in the magic age range of 18 to 29 … have been coming out in this year’s primaries at a rate 20 percent less than their mostly oblivious elders, a rate which in South Florida would put their impact on the election somewhere between sparse and infinitesimal." - Fred Grimm, The Miami Herald, August 27, 2014
Test Your Vocabulary with M-W Quizzes
Name That Antonym
Fill in the blanks to create an antonym of infinitesimal: a _ _ ron _mi _ _ l. The answer is …
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