Useful Abbreviations

Quick Equivalents
3 teaspoons = 1 tablespoon
2 tablespoons = 1 ounce
8 ounces = 1 cup
16 ounces = 1 pound
2 cups = 1 pint
2 pints = 1 quart
4 quarts = 1 gallon
1 kilogram = approx. 2.2 pounds
1 tablespoon = approx. 15 milliliters

Volume vs Weight - A Quick Discussion
Most American recipes are written with ingredients given in volume, much to the irritation of metric users everywhere.  Not only is this confusing to metric users, it's frustrating to beginning cooks trying to convert recipes.  Let's start off by defining what volume and weight are - as they are two very different creatures.

Volume is how much space an object takes up.  Weight is how heavy something is. So far, simple.  When measuring liquids, volume and weight are pretty much the same - a cup is 8 ounces, and a pint is 16 ounces, hence the saying, "a pint is a pound the world around."  The kicker is dry ingredients - weight and volume are not the same for dry ingredients, and this is a fact not taught to many beginning cooks.

Follow me here - let me illustrate.  Let's say you have measuring cup filled with feathers, and a second identical cup filled with rocks.  They take up the same amount of space (volume) but they do not weigh the same (weight).  Anytime you are measuring dry ingredients in cups, you are really measuring by volume, not weight.  The best cooking example I can think of is cheese, and I encourage you to check me on this.  There are a lot of casseroles that call for 2 cups of shredded cheese.  This is the most frequent size that pre-shredded cheese is sold in.  2 cups equals 16 ounces, right?  Wrong.  2 cups of shredded cheese is 8 ounces.  Go on, go to the fridge, and look - or check the dairy case when you go to the store tomorrow.  This is measuring in volume, not weight.

If a recipe measures dry ingredients in cups, use those measuring cups, even if you are feeling lazy and don't want to dirty up another cup.  This will ensure your results will be what the recipe's author intended.  Plus, when converting a recipe to serve more or less people, don't convert dry ingredient measurements into ounces to avoid fractions.  (I teach math - so don't think I don't know people do that.  :P)