The perfumed outermost layer of citrus fruits is called the zest. In the case of lemons its yellow, limes its green, and with oranges its orange. Underneath the zest is a bitter white pith. Together, the zest and pith make up the rind, which is a general term for the outside of a fruit, that term isn't limited to citrus, for instance watermelon have a rind.
What makes a rind attractive in recipes is its color and the aromatic oils found in it that can life an ordinary flavor in your recipe to new heights. From an average size lemon, you’ll get about 2 teaspoons finely grated zest, whereas with larger ones you can get nearly a tablespoon and small ones about 1 teaspoon. Limes on the other hand are much more stingy. It’s hard to get more