noun, Cell Biology.
one of the minute cells arising from the unequal meiotic divisions of the ovum at or near the time of fertilization.
(physiol) a tiny cell containing little cytoplasm that is produced with the ovum during oogenesis when the oocyte undergoes meiosis
polar body n.
Either of two small cells formed by the ovum during its maturation, the first usually released just before ovulation and the second not until after the ovum has been discharged from the ovary and penetrated by a sperm cell.
One of the small cells that are produced during the development of an oocyte and ultimately degenerate. A polar body contains one of the nuclei derived from the first or second meiotic division but little or no cytoplasm. See Note at oogenesis.
- Polar bond
polar bond A type of covalent bond between two atoms in which electrons are shared unequally. Because of this, one end of the molecule has a slightly negative charge and the other a slightly positive charge. See more at covalent bond.
noun 1. Geology. the icecap situated at either end of the earth’s poles. 2. Astronomy. either of the two bright areas around the poles of the planet Mars, consisting of water ice and frozen carbon dioxide. polar cap
- Polar cataract
polar cataract n. A capsular cataract limited to the anterior or posterior polar region of the lens.
noun 1. either the Arctic or the Antarctic Circle. noun 1. a term for either the Arctic Circle, Antarctic Circle polar circle The Arctic Circle or the Antarctic Circle.