any instrument used to measure the size and number of dust particles per unit volume in the atmosphere.
- Nucleus fastigii
nucleus fastigii nucleus fas·tig·i·i (fā-stĭj’ē-ī’, -stī’jē-) n. The most medial of the deep cerebellar nuclei, near the midline in the white matter underneath the vermis of the cerebellar cortex, receiving axons of Purkinje cells and fibers from the vestibular nerve and nuclei.
- Nucleus gracilis
nucleus gracilis nucleus grac·i·lis (grās’ə-lĭs) n. The medial of the three nuclei of the dorsal spinal column, receiving dorsal root fibers conveying sensory innervation of the leg.
- Nucleus of solitary tract
nucleus of solitary tract n. A slender cell column that extends through the dorsal part of the medulla oblongata, is the visceral sensory nucleus of the brainstem, and receives the afferent fibers of the vagus, glossopharyngeal, and facial nerves via the solitary tract.
[noo-klahyd, nyoo-] /ˈnu klaɪd, ˈnyu-/ noun, Physics. 1. an atomic species in which the atoms all have the same atomic number and mass number. 2. an individual atom in such a species. /ˈnjuːklaɪd/ noun 1. a species of atom characterized by its atomic number and its mass number See also isotope n. 1947, from nucleus […]