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.
external respiration. work of inhaling and exhaling gases between the respiratory system and the external environment. internal respiration. exchange that takes place within the body; work of body cells taking on O2 from the blood and giving back CO2 (waste) to be transported by the blood to the lungs for exhalation. nas/o, rhin/o.