capability of the body of distributing inhaled oxygen to muscle tissue during increased physical effort.
Also called Darwinian fitness. Biology.
  1. the genetic contribution of an individual to the next generation's gene pool relative to the average for the population, usually measured by the number of offspring or close kin that survive to reproductive age.
  2. the ability of a population to maintain or increase its numbers in succeeding generations.

Origin of fitness

First recorded in 1570–80; fit1 + -ness Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for fitness

Contemporary Examples of fitness

Historical Examples of fitness

  • It did not occur to him to question his fitness for the work.

    Within the Law

    Marvin Dana

  • The young girl no longer listened to these reasons of the fitness of things.

    The Dream

    Emile Zola

  • Only this very morning I read her a sermon upon 'Propriety, and the fitness of things.'

    The Channings

    Mrs. Henry Wood

  • The place had an Homeric simplicity and beauty which touched his sense of fitness.

    A Singer from the Sea

    Amelia Edith Huddleston Barr

  • Candidates must only be proposed for their fitness, and opposed on the ground of unfitness.



British Dictionary definitions for fitness



the state of being fit
  1. the degree of adaptation of an organism to its environment, determined by its genetic constitution
  2. the ability of an organism to produce viable offspring capable of surviving to the next generation
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

Word Origin and History for fitness

1570s, from fit (adj.) + -ness.

Online Etymology Dictionary, © 2010 Douglas Harper

fitness in Medicine




The state or condition of being physically sound and healthy, especially as the result of exercise and proper nutrition.
A state of general mental and physical well-being.
The state of being suitably adapted to an environment.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.