The Collaborative International Dictionary
Frank \Frank\, n. [See Frank, a.] The privilege of sending letters or other mail matter, free of postage, or without charge; also, the sign, mark, or signature denoting that a letter or other mail matter is to go free of postage. Called also the franking privilege.
I have said so much, that, if I had not a frank, I must
burn my letter and begin again.
--Cowper.
Usage examples of "franking privilege".
As a member of the armed forces of the United States serving overseas, the sender was given the franking privilege.
They were, however, given a few annuities, which boiled down eventually to 1) a franking privilege so postage was unnecessary on their letters, 2) a small annual dole, 3) subscriptions to current medical journals (now filled more with electronic data pertinent to phymechs than surgical techniques) and 4) honorary titles.