Lockout/tagout is specific set safety related practices and procedures which reduce the risk of harm from the unexpected activation of machinery or energization of electrical systems during maintenance activities. These procedures require workers engaged in service activities to disconnect the affected systems and either lock or tag the systems to prevent them from being reactivated by other workers who are unaware of the maintenance.
Standardized lockout/tagout procedures are mandated by workplace safety regulations by legislation in most countries. see your local legislation for specific practices in your location.
Source: CDX Global & Wikipedia - en.wikipedia.org
