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body mass index

American  
[bod-ee mas in-deks] / ˈbɒd i ˌmæs ˌɪn dɛks /

noun

  1. an index for assessing overweight and underweight, obtained by dividing body weight in kilograms by height in meters squared: a measure of 25 or more is considered overweight.


body mass index British  

noun

  1.  BMI.  an index used to indicate whether a person is over- or underweight. It is obtained by dividing a person's weight in kilograms by the square of their height in metres. An index of 20–25 is normal

"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

body mass index Scientific  
/ bŏdē /
  1. A measurement of the relative percentages of fat and muscle mass in the human body, in which weight in kilograms is divided by height in meters squared. The result is used as an index of obesity.


Etymology

Origin of body mass index

First recorded in 1955–60

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.

See Examples For:

Machines in supermarkets, leisure centres and libraries can assess body mass index, blood pressure, heart health and body fat in around ten minutes.

From BBC Jun. 21, 2026

The participants had a median age of 69 years and a median body mass index of 28.4.

From Science Daily Jun. 17, 2026

It also gave the president the exact height and weight ratio to keep him right under an “obese” body mass index, a designation so convenient as to be laughable.

From Salon Jun. 1, 2026

Current prescribing criteria center on body mass index thresholds and glycemic targets, metabolic markers that tell us something about a patient’s need for weight loss but nothing about their underlying GLP-1 physiology.

From Slate Mar. 22, 2026

Food intake predicts body mass index according to a monotonically increasing relation.

From "The Sense of Style" by Steven Pinker

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