aer·o·bics (â-r??b?ks)n. (used with a sing. or pl. verb)1. A system of physical conditioning designed to enhance circulatory and respiratory efficiency that involves vigorous sustained exercise, such as jogging, swimming, or cycling.2. A program of physical fitness that involves such exercise.[From aerobic.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.aerobics (???r??b?ks) n (functioning as singular) any system of sustained exercises designed to increase the amount of oxygen in the blood and strengthen the heart and lungs aer?obicist nCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014aer?o?bics (???ro? b?ks) n. (used with a pl. v.) any of various sustained exercises, as jogging, calisthenics, and vigorous dancing, designed esp. to stimulate and strengthen the heart. [1965?70; probably shortened from aerobic exercises on the model of calisthenics] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.aerobicsa form of physical activity characterized by strenuous exercise of many muscle groups and intended to increase muscle tone and cardiovascular fitness. ? aerobic, adj.See also: Athletics-Ologies & -Isms. Copyright 2008 The Gale Group, Inc. All rights reserved.