A stamp that has been used, normally evidenced by a postal or fiscal cancellation.
The Stanley Gibbons catalogue reference used to identify and catalogue stamps.
The catalogue value quoted from Stanley Gibbons. It is not the same as the UPA auction estimate or a guaranteed selling price.
A stamp produced without perforations separating it from adjoining stamps.
An abbreviation for watermark: a design or pattern incorporated into the stamp paper during manufacture.