Warfare refers to the conduct of conflict between opponents, and usually involves escalation of aggression from the proverbial "war of words" between politicians and diplomats to full-scale armed conflicts, waged until one side accepts defeat or peace terms are agreed on. Warfare between groups, and even more so between military organisations, require a degree of planning and application of military strategy to be conducted effectively in reaching their stated or assumed objectives and goals.

Warfare by other means

A commitment of any given society to a conflict invariably involves methods of warfare that stop short of those requiring direct armed confrontations, but which nevertheless inflict damage to the opponent society by affecting its motivation to resist, or its standard of living. Usually this is exhibited by affecting the economy of the opponent, one example from the 20th century being the imposition of economic sanctions, or the effect on the morale of the opponent by commitment of the society as a whole to the conflict.

• Economic warfare
• Total war

Military operations marked by a specific characteristic

One to categorize warfare is by differentiation between conventional versus unconventional, where conventional warfare involves well-identified, armed forces fighting one another in a relatively open and straightforward way without weapons of mass destruction. "Unconventional" refers to other types of war which can involve raiding, guerrilla, insurgency, and terrorist tactics or alternatively can include nuclear, chemical, biological warfare or using propaganda with pressure groups to invoke certain feelings much like August Keim did in Wilhelmine Germany.

All of these categories usually fall into one of two broader categories: High intensity and low intensity warfare. High intensity warfare is between two superpowers or large countries fighting for political reasons. Low intensity warfare involves counterinsurgency, guerilla warfare and specialized types of troops fighting revolutionaries.

• Asymmetric warfare
• Conventional warfare
• Chemical warfare
• Guerilla warfare
• Unconventional warfare

Environment as a factor

The environment, and particularly the prevailing terrain and climatic conditions in the area of operations, have always influenced the use of armed forces, including the doctrines, weapon and logistic technologies employed.

Terrain-based warfare factors

Largely related to the geographic location the following types of warfare refer to special consideration of combat in conditions other than those of a temperate climate of European regions.

• Arctic warfare
• Desert warfare
• Jungle warfare
• Mountain warfare

Human-based warfare factors

Some combat operations are influenced by the effect of human actions on the environment, in either modifying it, or affecting the normal functioning of the enemy troops under combat conditions.