Zest source

LEMONRIND

Think of the outer yellow layer you might grate for a tangy kick in recipes or drinks. It's not the juice but what protects the fruit.

"Zest source" is a straightforward clue pointing to the outer part of a citrus fruit used for flavor. The answer, LEMONRIND, combines "lemon" (a common citrus fruit) with "rind" (the tough outer skin), which is where the zest comes from. It’s a direct definition with no hidden wordplay—just a literal description of where you’d find zest in the kitchen.