Registered Mail : First class mail with a numbered receipt that gives guarantee that customer will get the item and it will not be lost in the mail.

Reissue : An official reprinting of a stamp that was no longer being printed.

Remainders : Stamps remaining in official stocks after becoming obsolete.

Replicas : Reproductions of stamps sold during the early days of collecting. Usually printed in one color on a sheet containing a number of different designs. Replicas were never intended to deceive either the post office or the collector.

Reprint : A stamp printed from the original plate after the issue is no longer valid for postage. Official reprints are sometimes made for presentation purposes, official collections, etc., and are often distinguished in some way from the "real" ones.

Revenue Stamps : Stamps issued as proof of payment of certain taxes but not valid for postage.

Roulette : Stamps separated by a series of cuts instead of perforations.