Abbreviations and Glossary

Stamps:

CTO - Cancelled to Order: A stamp that appears to be used (i.e. it has a postmark), but still has gum on the reverse. They are so-called because they are cancelled by the issuing postal service before being sold to stamp collectors or dealers - for example, to meet collector demand, or so that they can no longer be used on mail.

F/U - Fine Used: Postally used, with a particularly clean or neat postmark; better than 'good used'

G/U - Good Used: Postally used, but with a postmark that is less neat, or covers more of the design, than a stamp that is 'fine used'

M/M - Mounted Mint: Unused, but previously hinged; less desirable than 'unmounted mint', but still collectable

U/M - Unmounted Mint: Unused and never hinged, as bought from the post office; more desirable than 'mounted mint'