n (Philately) philately a cover, usually an envelope, postmarked on the first day of the issue of its stamps
first′-day` cov′er
n. an envelope bearing a canceled stamp and postmarked on the stamp's first day of issue at the postal station where it was first released. [1935–40, Amer.]Translations
first-day cover
first-day cover
Philately a cover, usually an envelope, postmarked on the first day of the issue of its stamps