The term "combat" (French for fight) typically refers to armed conflict between military forces in warfare, whereas the more general term "fighting" can refer to any violent conflict. Combat violence can be unilateral, whereas fighting implies at least a defensive reaction. However, the terms are often used synonymously.

Combat may take place under a certain set of rules or be unregulated. Examples of rules include the Geneva Conventions (covering the treatment of soldiers in war), medieval Chivalry, and the Marquess of Queensberry rules (covering boxing).

Combat in warfare involves two or more opposing military organizations, usually fighting for nations at war (although guerrilla warfare and suppression of insurgencies can fall outside this definition). Warfare falls under the laws of war, which govern its purposes and conduct, and protect the rights of soldiers and non-combatants.

Combat may be armed (using weapons), or unarmed (not using weapons). Hand-to-hand combat (mêlée) is combat at very close range, feeling the opponent with the body (striking, kicking, strangling, etc.) and/or with a mêlée weapon (knives, swords, batons, etc.), as opposed to firing.

Hand-to-hand combat can be further divided into three sections depending on the distance and positioning of the combatants:

• Stand-up fighting
• Clinch fighting
• Ground fighting