A "radif" is a recurring phrase or word that appears at the end of each couplet in a ghazal, a form of Persian poetry. It serves as a structural element, providing rhythm and unity to the poem. The radif is often accompanied by a qafia, which is a rhyming word that precedes it. In Persian literature, the use of a radif enhances the emotional impact of the poem, allowing poets to express complex feelings and themes. This technique has been widely adopted in various languages influenced by Persian poetry, showcasing its significance in literary traditions.