Term: A FDC (First Day Cover)
is a cover with a stamp canceled with either a commemorative, specially designed,
pictorial postmark or a regular postmark with the date of the official release of the stamp.
The postmark usually indicates the date the stamp was issued and the city where it was first released.
Some countries issue stamps on one date, but the postmark is applied to FDCs weeks or even months after the date of release.
Most Postal authorities design FDCs that highlight the same theme or design as the stamp.
Other countries have a regular design that is used for all FDCs regardless of topic.