The only difference between the two is a nickels worth of confusion. Some words in recipe language are interchangeable – grated lemon peel and lemon zest being a prime example. To get lemon zest for a recipe, just the outer portion of the lemon peel is lightly grated.  Lemon zest is created  from the fragrant outer layer of the lemon peel that does not reach into the white pith of the lemon peel. Grating a little lemon peel (lemon zest) into a recipe adds a blast of fat-free, citrus flavor. Lemon zest is frequently added to chicken dishes.
The actual peel (rind, skin) of a lemon is rarely used in recipes unless one is making candies lemon peel.