Simply, rose water is a flavored water that is made by steeping rose petals in water. It's often used in perfume, but it has a wide variety of uses in cooking. It tastes much like you'd imagine a rose tastes. Floral and lightly sweet. It's easy to use way too much of it, so if you've never used it before, start with less and taste; add more if you need. You can purchase rose water in the ethnic section of most grocery stores (it's often used in Middle Eastern dishes), or online retailers like Amazon. It usually comes in a glass bottle, and it's clear.