DIA or Dia may refer to:
Diana, Princess of Wales (Diana Frances; née Spencer; 1 July 1961 – 31 August 1997), was the first wife of Charles, Prince of Wales, who is the eldest child and heir apparent of Queen Elizabeth II.
Diabetes mellitus (DM), commonly referred to as diabetes, is a group of metabolic diseases in which there are high blood sugar levels over a prolonged period.
Diazepam, first marketed as Valium, is a medication of the benzodiazepine family that typically produces a calming effect.
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose or liquid bowel movements each day.
Diamond (pronunciation: /ˈdaɪəmənd/ or /ˈdaɪmənd/) is a metastable allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice.
Dianne Goldman Berman Feinstein (/ˈfaɪnstaɪn/; born Dianne Emiel Goldman; June 22, 1933) is the senior United States Senator from California.
Diabetes mellitus type 1 (also known as type 1 diabetes) is a form of diabetes mellitus in which not enough insulin is produced.
Diane Ernestine Earle Ross (born March 26, 1944), known professionally as Diana Ross, is an American singer, songwriter, actress, and record producer.
Dialectic or dialectics (Greek: διαλεκτική, dialektikḗ), also known as the dialectical method, is a discourse between two or more people holding different points of view about a subject but wishing to establish the truth through reasoned arguments.