root mean square

American

noun

Mathematics.

the square root of the arithmetic mean of the squares of the numbers in a given set of numbers. rms

root mean square British

noun

rms. the square root of the average of the squares of a set of numbers or quantities

the root mean square of 1, 2, and 4 is √[(1² + 2² + 4²)/3] = √7

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of root mean square

First recorded in 1890–95

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The root mean square speed of H2 molecules at 25 °C is about 1.6 km/s.

From Textbooks • Feb. 14, 2019

In the KMT, the root mean square speed of a particle, urms, is defined as the square root of the average of the squares of the speeds with n = the number of particles:

From Textbooks • Feb. 14, 2019

What is the root mean square speed of a N2 molecule at 25 °C?

From Textbooks • Feb. 14, 2019

What is the ratio of the root mean square speeds, urms, of the two gases?

From Textbooks • Feb. 14, 2019

Note that the most probable speed, νp, is a little less than 400 m/s, while the root mean square speed, urms, is closer to 500 m/s.

From Textbooks • Feb. 14, 2019

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