Bug Defect Tracking Question:

Various categories of defects:

Omission: Failure to include or gather a requirement which causes a defect.
Lack of knowledge: When failure to understand a requirement due to lack of knowledge causes a defect.
Miscommunication: When incorrect or communication or misunderstandings in communication cause a defect to occur.
Accidental: When the requirement is gathered correctly and knowledge is available and even then a mistake is done.