Cups in a recipe are always measuring cups, not teacups.
Measuring cups come in two different types. Individual pieces for 1 cup, 1/2 cup, 1/3 cup and 1/4 cup. These individual pieces are used for dry ingredients. There are also larger glass or plastic cups with markings on the side where you fill the cup to the appropriate level marked with a measure line. This type is used for liquids.
Alix gave you a chart for flours. Just about water-based liquids are the same. A cup is 8 fluid ounce and 8 ounces on the scale.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan