What constitutes "reasonable" varies in both statutory law and case law. Unreasonable physical punishment may be charged as assault or under a separate statute for child abuse. Many countries, including some US states, also permit the use of corporal punishment for children in school. In English law, s. 58 Children Act 2004 limits the availability of the lawful correction defense to common assault under s. 39 Criminal Justice Act 1988. Prevention of crime
This may or may not involve self-defense in that, using a reasonable degree of force to prevent another from committing a crime could involve preventing an assault, but it could be preventing a crime not involving the use of personal violence. Defense of property
Some jurisdictions allow force to be used in defense of property, to prevent damage either in its own right, or under one or both of the preceding classes of defense in that a threat or attempt to damage property might be considered a crime (in English law, under s5 Criminal Damage Act 1971 it may be argued that the defendant has a lawful excuse to damage property during the defense and a defense under s3 Criminal Law Act 1967) subject to the need to deter vigilantes and excessive self-help. Furthermore, some jurisdictions, such as Ohio, allow residents in their homes to use force when ejecting an intruder. The resident merely needs to assert to the court that they felt threatened by the intruders presence.
These include:

Assault with further specific intent
Acts done to the person with intent to murder
Wounding or grievous bodily harm
Use or possession of a weapon to resist arrest

Assault causing certain injuries
Actual bodily harm – the term is not defined in the Crimes Act, but case law indicates actual bodily harm may include injuries such as bruises and scratches, as well as psychological injuries if the injury inflicted is more than merely transient (the injury does not necessarily need to be permanent)
Wounding – where there is breaking of the skin;
Grievous bodily harm – which includes the destruction of a foetus, permanent or serious disfiguring, and transmission of a grievous bodily disease

Assault causing death
Death
Death when intoxicated (in regards to the offender)

Canada
Assault is an offence under s. 265 of the Canadian Criminal Code. There is a wide range of the types of assault that can occur. Generally, an assault occurs when a person directly or indirectly applies force intentionally to another person without their consent. It can also occur when a person attempts to apply such force, or threatens to do so, without the consent of the other person. An injury need not occur for an assault to be committed, but the force used in the assault must be offensive in nature with an intention to apply force. It can be an assault to "tap", "pinch", "push", or direct another such minor action toward another, but an accidental application of force is not an assault.