a postal envelope for standard-size business letters 8 1 / 2 × 11 in. (20 × 28 cm), measuring about 4 1 / 2 × 9 in. (11 × 23 cm).
BUSINESS ENVELOPE
Meaning of BUSINESS ENVELOPE in English
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012