Triage is –
Triage 

When the quantity and severity of injuries overwhelm the operative capacity of health facilities, a different approach to medical treatment must be adopted.
The usual principle of first come, first treated", is not followed in mass emergencies.
Triage consists of rapidly classifying the injured and the likelihood of their survival with prompt medical intervention.
Higher priority is granted to victims whose immediate or long-term prognosis can be dramatically affected by simple intensive care.
Moribund patients who require a great deal of attention, with questionable benefit have the lowest priority.
Treating the most serious cases
Categorisation of the patients and treating them according to the available resource
Cautery burns
Treating mentally ill patients