This question is based on General Literary Principles. A line or a group of lines repeated in the course of a poem is called
Answer Details
A line or group of lines repeated in the course of a poem is called a "refrain." A refrain is a poetic device in which a line or group of lines is repeated at regular intervals throughout a poem. The repetition of the refrain can serve to emphasize a particular idea or theme, create a musical effect, or provide structure and coherence to the poem. The refrain can be a single word, phrase, or entire stanza that is repeated, and it is often used in poetry forms such as ballads, villanelles, and sestinas.