Could you tell me which word ID stands for?
(identity or identification)
Could be either one.
ID is used (normally) in phrases like "ID Card" or "ID Badge". In both of these examples, either Identity Card/Badge or Identification Card/Badge would work.
Not a teacher, 53-year-old American.
… and that’s my opinion
Further to opa's excellent reply, ID can also mean identify.
'Have you been able to ID the corpse yet, inspector?'