Horology glossaryDefined term / serial-number
Serial Number
A unique number identifying an individual watch, distinct from the reference number, which identifies only the model.
Authentication note
Why this detail matters.
A serial number can be checked against known production date ranges and, in a registry like Watch Safe's, against a record for that specific watch. A serial that falls within a plausible range only proves such a number was issued, though, not that this particular watch is the one it was issued to, so matching the serial to the case, movement, and documents still matters.