Excellent work, Colin Robinson. However, I think I'd disagree. The reality is we all knew what OP meant because the colloquial (non-CS) definition of unique is

Excellent work, Colin Robinson. However, I think I'd disagree. The reality is we all knew what OP meant because the colloquial (non-CS) definition of unique is just "very unusual". It isn't often in meatspace that humans are trying to distinguish completely physically unique items, so such a constrained definition is understandably rare in normal conversation.