What is a Promise Ring. A promise ring, sometimes known as a pre-engagement ring, is a simple piece of jewelry that is given as a symbol of a committed, monogamous relationship. In some cases, the promise ring symbolizes purity and a decision to remain celibate until marriage.
Noun. 1. external respiration-the bodily process of inhalation and exhalation; the process of taking in oxygen from inhaled air and releasing carbon dioxide by exhalation. breathing, respiration, ventilation. artificial respiration-an emergency procedure whereby breathing is maintained artificially.
Definition of EXTERNAL RESPIRATION. : exchange of gases between the external environment and a distributing system of the animal body (as the lungs of higher vertebrates or the tracheal tubes of insects) or between the alveoli of the lungs and the blood â compare internal respiration.ADVERTISEMENT.noun.efinition of EXTERNAL RESPIRATION. : exchange of gases between the external environment and a distributing system of the animal body (as the lungs of higher vertebrates or the tracheal tubes of insects) or between the alveoli of the lungs and the blood â compare internal respiration. ADVERTISEMENT. noun.