Since the concept of being below is itself somewhat vague, scientists define the nadir in more rigorous terms. Specifically, in astronomy, geophysics and related sciences (e.g., meteorology), the nadir at a given point is the local vertical direction pointing in the direction of the force of gravity at that location.
anatomical dead space. In pulmonary physiology, the area in the trachea, bronchi, and air passages containing air that does not reach the alveoli during inspiration and is not involved in gas exchange. This is termed dead space because the air does not reach the alveoli and is not involved in gas exchange. Normal anatomical dead space is 2.2 ml/kg or 1 ml/lb.
deadÂ·eye (dÄdâ²Ä«â²) n. 1. Nautical A flat hardwood disk with a grooved perimeter, pierced by three holes through which the lanyards are passed, used to fasten the shrouds. 2. Slang An expert shooter: a deadeye with the rifle. deadeye (ËdÉdËaÉª) n. 1. (Nautical Terms) nautical either of a pair of disclike wooden blocks, supported by straps in grooves around them, between which a line is rove so as to draw them together to tighten a shroud. Compare bull's-eye 9. 2. (Shooting) chiefly informal US an expert marksman. deadâ¢eye