See cosmic background radiation
background radiation back·ground radiation (bāk’ground’)
Relatively constant low-level radiation from environmental sources such as building materials, cosmic rays, and ingested radionucleides in the body.
Low-level radiation at the surface of the Earth that comes from cosmic rays and from small amounts of radioactive materials in rocks and the atmosphere.
having a back, backing, setting, or support (often used in combination): a low-backed sofa. (of fabric) having an extra set of threads in either the warp or the weft to provide added warmth. Compare double cloth. Photography. (of a film or plate) coated with a substance for absorbing light and thereby reducing halation. the rear […]
noun (Brit, informal) a ride on the back of someone’s bicycle
aid or support of any kind. supporters or backers collectively. something that forms the back or is placed at or attached to the back of anything to support, strengthen, or protect it. Theater. a curtain or flat placed behind a window, entrance, or other opening in a stage set to conceal the offstage area. material […]
- Backing dog
noun (NZ & Austral) a dog that moves a flock of sheep by jumping on their backs