Did any one think the same

bluedigest, you might be interested in the following link to Linns which contains an extensive glossary of philatelic terms: www.linns.com/insights/glossary-of-philatelic-terms.html

After reading the link posted by mike, I still understand that cancel stamp is a used stamp. I don't see any difference. Isn't a stamp with a mark on it called cancelled. And I feel that is a used stamp. What other scenario am i missing here.

bluedigest Some postal administrations have cancelled stamps with very neat cancellations to sell to collectors without them ever going through the postal system, or being stuck on envelopes etc, so the stamps were never used and still have the pristine gum on the back. This was particularly common in East European countries like Czechoslovakia, Hungary and Poland under the Communists - and I have a Hungarian example dating back well before communist rule, to just after WW1. These stamps are cancelled but not used. They are termed "cancelled to order" or CTO, and the stamps have often been sold in bulk by the postal administrations to stamp dealers. 

Sometimes collectors will use more specific terms to avoid confusion when using the general term "used".

As mentioned above, and also additional examples:

cancelled-to-order (CTO) -- stamps sold by post office/administrations already canceled, no longer valid for postage, categorized as used in the stamp catalogs, but technically not postally used

pre-canceled -- stamps sold by post office that can be used by authorized mailers, they may or may not have a "cancel" mark (sometimes just a special rate designation printed), they do not require cancellation when mailed since they must be submitted directly to postal services (not normal mailstream), pre-cancels not sold to general public are by definition "used" in the catalogs, those available to general public are considered unused only if they still have original gum and used if they no longer have gum

favor-canceled -- stamps used for the payment of postage or services, receive postal cancel to indicate payment, but handed back to the collector instead of being put into the mailstream

postally used -- stamps that physically went through the mailstream, they usually have cancels but not always

Hope I succeeded in making something simple complicated.

So in a nutshell to clarify what Craig posted: canceled stamps aren't always postally used, and postally used stamps aren't always cancelled (yeah, they often don't cancel stamps nowadays, especially on packages or oversized envelopes).