rosa (Noun) — A disease caused by deficiency of niacin or tryptophan (or by a defect in the metabolic conversion of tryptophan to niacin); characterized by gastrointestinal disturbances and erythema and nervous or mental disorders; may be caused by malnutrition or alcoholism or other nutritional impairments.
rosa (Noun) — Large genus of erect or climbing prickly shrubs including roses.
rosa (Adverb) — In secret or covertly. ex. "held a meeting sub rosa to avoid general criticism"