In software development, defects are usually categorized by severity and priority.
A severity is defined as the impact the defect has on the system. In other words, the severity helps answer questions such as: Which process or flow is the defect affecting? Are users blocked by the defect? Is there a workaround?
The severity ranges from Critical or Blocker to Minor or Cosmetic.
A priority indicates the urgency by which the defect should be fixed. The priority helps then answer questions such as: How urgent is the defect? When should the defect gets fixed?
The priority values ranges from High to Low.