radiation background radiation http://orcid.org/0000-0002-5111-7263, https://orcid.org/0000-0001-9227-0670 For uses involving experimentation or radiation therapy, use "anthropogenic background radiation" instead. Use this concept to indicate source is a mixture of anthropogenic and naturally occurring (ambient), or unknown or if the discrimination is not sought. The ambient radiation in a defined environment emanating from natural or anthropogenic sources. background radiation