REGULAR - A term used to describe any commercial envelope that does not have a window.
REMITTANCE ENVELOPE - A booklet or side seam style envelope with a long wallet type seal flap covering most of the back of the envelope. Used as a collection envelope. Most common sizes being of the commercial and official sizes #6 1/4, #6 3/4, and #9. Boxed with flaps extended.
REMOISTENABLE SEAL GUM - Commonly referred to as regular gum. Requires moistening to achieve a seal. There are two main types of seal gum. They are dextrine, a natural vegetable bi-product, and resin, a synthetic substance. Most remoistenable gum used today is a mixture of the two types.
