Cover franked with a postage stamp or set of stamps postmarked on the first day of issue.
cover cancelled on the day a stamp is issued, in the city in which it is released. (Modern First Day Covers may actually be cancelled up to 30 days after the date of issue, and not necessarily in the city whose postmarks they bear.) First Day Covers may be addressed or unaddressed, and with or without cachets. See Unofficial First Day Cover and Second Day Cover.
A cover bearing a stamp (or set of stamps) posted on the day of issue. It is a very popular collectible among philately buffs. First Day Covers usually have an illustration depicting an aspect of a subject of the issue and often include a card or info sheet which gives more details about the subject.
A cover bearing new stamps cancelled on the day of issue, normally with a special "First Day" postmark.
an envelope bearing postage stamps with a postmark of the first day of their issue
an envelope, postcard, etc
a special envelope to mark the first day of issue of a new set of stamps
a specially designed envelope that marks the first day of issue for commemorative stamps
A cover bearing stamps postmarked on their day of issue.
An envelope with a stamp cancelled on its first day of sale.
Cover with a new stamp(s) or postal indicia, cancelled on the First Day.
An envelope bearing a cancellation date that represents the first day of issue for that stamp. First Day Covers can be acquired from the issuing Post Office for a period of 30 days after the actual issue date.
Envelope with stamp canceled on the first day of issue. Most covers from 1935 on are cacheted. Cachets are designs which relate to the topic of the stamp being issued.
For some time the first day of issue of a new stamp has been marked by special ceremonies. It is also the date which appears on the cancels of First Day Covers (FDC) or, as they are sometimes called, First Day of Issue covers (FDOI). Most FDCs are not cancelled on the date as the process goes on for weeks due to the quantity of covers to be processed.
An envelope with a new stamp and cancellation showing the date the stamp was issued. The postmark or cancellation applied to that stamp is dated on the date and at the location that the postage stamp is first placed on sale. Most collectors also want a printed design on the envelope that explains or provides additional information about the stamp. This printed design is called a cachet. Click for larger view Special envelopes, or covers, with postage stamps and cancellations are also issued for various special events such as First Flights, Presidential Inaugurations, Sports, Patriotic, Philatelic Conventions, XMAS, Special Events, etc. Click for larger view
A cover bearing postage stamps postmarked and sent through the post on the first day they were officially authorised for use. Special postmarks have been used for this purpose in many countries since the late 1930s.