See also: centi-gray English Etymology From centi- + gray. Noun centigray (plural centigrays) A derived unit of measure for absorbed dose of radiation, equal to the hundredth part (1%) of a gray, that is, 0.01 Gy. Alternative form: cGy (symbol) Near-synonyms: rad, rd (same physical quantity) See also Appendix on SI Units Remove adsWikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads