首日封 Traditional form: 首日封 Pinyin (reading): shǒurìfēng Definitions: first day cover (philately) Characters: 首 - chief, head, leader 日 - sun; day; daytime 封 - envelope, letter; to confer, to grant; feudal Traditional characters: 首 - chief, head, leader 日 - sun; day; daytime 封 - envelope, letter; to confer, to grant; feudal