[ kahr-dee-oh ]

  1. aerobic exercise that stimulates and strengthens the heart and lungs: I mostly use weights, but I always add a little cardio into my routine.

  1. of or relating to aerobic exercise: The class begins with a slow and steady warmup, and then it switches to a cardio workout.

  2. of or relating to the heart; cardiovascular: He's a hugely successful cardio surgeon.

Origin of cardio

First recorded in 1960–65

Other definitions for cardio- (2 of 2)


  1. a combining form meaning “heart,” used in the formation of compound words: cardiogram.

Origin of cardio-

<Greek kardio-, combining form of kardía
  • Also especially before a vowel, cardi-. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use cardio in a sentence

  • I would particularly mention, however, a group of cardio-vascular troubles that lie between these two extremes.

  • Perhaps such cases of cardio-vascular disease might be most correctly said to be due to the wear and tear of life.

  • Beginning with the simplest kind of cardio-vascular disorder, let us see what the prognosis is in tobacco heart.

  • So much for the general prognosis in each of these kinds of cardio-vascular disorder and disease.

  • The wide distribution of these pharyngo-laryngo-esophago-pulmano-cardio-gastric nerves gives ample opportunity for reflexes.

    Psychotherapy | James J. Walsh

British Dictionary definitions for cardio-


combining form
  1. heart: cardiogram

Origin of cardio-

from Greek kardia heart

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