You don't know what rusk is??? Well, you certainly know various forms of rusk – you just don't know that there is a category by that name.

Rusk is a raised bread, cracker, or cake that has been dried to a crisp and browned – either toasted in an oven or baked a second time after slicing. It can be plain or sweet. The best-known examples are the German Zweiback, the Italian biscotti, and the French biscotte. Technically, toast is a form of rusk, as long as it's been dried all the way through. All of the various crispbreads produced by the Swedish company Wasa are rusks.

The word comes from the Spanish rosca, literally "a spiral," but referring to a twisted, crunchy roll of bread. Rosca comes from the Vulgar (spoken) Latin rosicare, meaning "to gnaw."

You can buy rusk in various forms at the supermarket and online. Occasionally you'll find it going by the name rusk, although often you have to look for the specific rusk you have in mind – biscotti, Zweiback, etc. You can also easily make your own.

You can delight/confuse/infuriate your spouse/children/guests the next time you make him/her/them breakfast, by asking if he/she/they would like "some rusk with your eggs?" or "butter on your rusk?" or "some rusk to dip in your cocoa?" The possibilities are almost endless.