Protoplanetary disk
protoplanetary disk
(prō’tə-plān’ĭ-těr’ē)
A rotating disk of dust and gas that surrounds the core of a developing solar system. It may eventually develop into orbiting celestial bodies such as planets and asteroids. See more at planetesimal.
Read Also:
- Protoplasm
noun 1. Biology. (no longer in technical use) the colloidal and liquid substance of which cells are formed, excluding horny, chitinous, and other structural material; the cytoplasm and nucleus. 2. Obsolete. the living matter of organisms regarded as the physical basis of life, having the ability to sense and conduct stimuli. noun 1. (biology) the […]
- Protoplasmic
noun 1. Biology. (no longer in technical use) the colloidal and liquid substance of which cells are formed, excluding horny, chitinous, and other structural material; the cytoplasm and nucleus. 2. Obsolete. the living matter of organisms regarded as the physical basis of life, having the ability to sense and conduct stimuli. noun 1. (biology) the […]
- Protoplasmic astrocyte
protoplasmic astrocyte n. An astrocyte found in the gray matter of the brain, having few fibrils and numerous branching processes.
- Protoplast
noun 1. Biology. the contents of a cell within the cell membrane, considered as a fundamental entity. the primordial living unit or cell. 2. a person or thing that is formed first; original; prototype. 3. the hypothetical first individual or one of the supposed first pair of a species or the like. noun 1. a […]
- Protopodite
noun, Zoology. 1. the basal portion of a two-branched crustacean leg or other appendage.