Rotating image of human brain, illustrating the lateral sulcus in the brain. The term sulcus (pl. sulci) is a general descriptive term for a furrow or fissure.
Halo may refer to: 1  Halo (religious iconography), a glow or ring of light around a head or person in art. 2  Halo (series), video game franchise.
Halogen Definition: A element located in Group VIIA of the periodic table. Halogens are reactive nonmetals having seven valence electrons. Examples: fluorine, chlorine, bromine, iodine. Return to the Chemistry Glossary Index. By Anne Marie Helmenstine, Ph.D.alogen Definition: A element located in Group VIIA of the periodic table. Halogens are reactive nonmetals having seven valence electrons. Examples: fluorine, chlorine, bromine, iodine. Return to the Chemistry Glossary Index. By Anne Marie Helmenstine, Ph.D.