The list here below is the abreviations and common terms that are widely used all over the world today, when one is grading postcards.

The continental size for a postcard is 4 x 6" (inch) or 15 x 10.5cm.The standard or regular size in postcards is a postcard that is 3½ x 5½" (inch) or 9 x 14cm  These postcards are not modern, as they are usually old.

An over sized postcard is any postcard that is larger than the continental size. A vast majority of the over sized postcards are 5 x 7" (inches). As these cards are a lot larger than all the others, the view is clearly more detailed.

The size of a modern postcard is 6½ x 4¾" (inches).

The over sized postcards are very popular with tourists, but not with a lot of postcard collectors, this is mainly because of their size. They are usually a lot harder to forward on to someone else, unless you know of someone who has a specific need for them. So if you get stuck with any just do as I do, and write a small letter or note or even a "hello, I'm thinking of you", on them and send them off to a friend or relative that doesn't collect postcards, but would appreciate the thought and the words received from you!