From Stamps of the World
The term "surcharge" in philately describes any type of overprint that alters the price of a stamp. Surcharges raise or lower the face value of existing stamps when prices have changed too quickly to produce an appropriate new issue, or simply to use up surplus stocks. They are also often used in temporary issues when another currency is needed (colonies, occupations). Thus they do not qualify as Definitives. It is also clear that an added cat Overprints on pages which show only the new value is redundant. Note that the French catalogue Yvert does not distinguish Surcharges from Overprints (all are named Timbres surchargés).
This category has the following 3 subcategories, out of 3 total.
Pages in category "Surcharges"
The following 709 pages are in this category, out of 709 total.