Defect triage is a process in software testing where it defines the order of defects which will be resolved according to the priority of severity or risks etc. It is also called Bug Triage. It is based on the severity and priority of the defects in software.
Severity means the degree of impact or amount of impact of the defect on the software or part of the application which is tested. Priority indicates the correct order in which the detected defects should be fixed or resolved.
So basically, Defect Triage helps the software testing team if the available resources are very few to fix the bugs in software.