A triad, a group of three, may refer to:

Computers

• Triad, group of three phosphor dots used in some computer monitors
• Triad C64, Commodore 64 cracking group
• Rise Of The Triad, a computer game
• TriadCity, a MUD with strong literary themes

Entertainment

• Triad, a 1967 song by David Crosby, with versions recorded by Jefferson Airplane on Crown of Creation, by Crosby, Stills Nash & Young on Four Way Street, and by the Byrds on The Notorious Byrd Brothers
• Triad, a 1976 album by Spontaneous Combustion.
• Triad, a song by progressive rock band Tool from their 2001 album Lateralus
• The Hong Kong Triad, a song by Thievery Corporation from their 2000 album The Mirror Conspiracy
• Triad (music), set of three notes, most commonly forming a diatonic tertian chord
• The Triad (Charmed), a fictional group of three powerful demons
• Triiad, a fictional alien species from the television series Hypernauts
• Triad, alias of fictional DC Comics super hero Triplicate Girl

History

• Welsh Triads, collections of Medieval Welsh legend and history

Medicine

• Triad (anatomy), structure in skeletal muscles, formed by a T tubule surrounded by sarcoplasmic reticulum
• Catalytic triad, biochemical term for three amino acid residues found within some proteases
• Beck's triad (cardiology), three typical symptoms of cardiac tamponade
• Beck's cognitive triad, three types of negative thought present in depression
• Charcot's triad, either of two sets of clinical signs, relating to multiple sclerosis or ascending cholangitis
• Currarino triad, three malformations with a genetic link
• Cushing's triad, a set of three signs showed by patients with head injuries
• Dieulafoy's triad, a classic sign of acute appendicitis
• Female athlete triad, three symptoms of low energy availability in female athletes
• Hutchinson's triad, a common pattern of presentation for congenital syphilis
• Meckler's triad, used to diagnose Boerhaave syndrome
• Virchow's triad, a set of three signs attributed to Rudolf Virchow describing the pathogenesis of venous thrombosis
• Whipple's triad, a set of three conditions proving hypoglycemia as the cause of a person's symptoms
• MacDonald triad, three childhood traits that are associated with anti-social personality disorder

Philosophy

• Triad, Pythagorean symbol for the number three

Places

• The Piedmont Triad, North Carolina, USA region

Relationships

• Triad, term for a relationship between three people,

Religion

• Triad, three deities commonly associated together.
• Triplism frequently occurring in religion and mythology

Science

• Triad, management system for environmental cleanup
• Triad Demand, UK electrical power demand measurement

Societies

• Triad, term for a group of three people as a unit of study
• Triad, a term that describes many branches of (criminal) Chinese underground society, such as those in Hong Kong and around the world

Sport

• Triad, a fictional ball sport within the Battlestar Galactica series