Glossary of Cooking Terms

Dust
"Dust with flour" is a common instruction in recipes, usually immediately following "grease the pan." The idea is to put a light coating over the surface which will help prevent sticking. When dusting a greased pan, you can use a shaker filled with the flour of choice and dust with a salting motion, or you can simply plunk a small scoop of flour into the pan and shake it back and forth, tapping the sides of the pan, until the whole area is coated. Then turn the pan over your trash can and tap again to remove the excess.
Lukewarm
The right temperature for proofing yeast. If you have a thermometer or temperature probe, 110F is ideal, but you can also get about the right temperature using the classic baby formula testing method, by sprinkling a few drops on the inside of your forearm. If the temperature feels neither particularly warm nor cold there, then it's about right. When proofing yeast it is better to err on the side of cool than hot. If too cool, the yeast will simply grow very slowly (it can in fact grow in your refrigerator), but if too hot, you kill the "yeastie beasties."
Proof (yeast)
This is a process of using lukewarm water, often with a small amount of "food" (e.g. sugar) to disolve dried yeast and then allow it to grow. If the yeast foams up it is still alive, and suitable to use in the recipe. If after several minutes the yeast does not foam up, either the water was too hot, way too cold, or the dry yeast is too old and has died. You can try again with more from the same batch and if you get the same results, you'll need to buy fresher yeast. See also "lukewarm" for a description of the right temperature to use.