A ballad is a form of verse that tells a story, often set to music. Ballads were originally "dance songs" and were composed in couplets with refrains in alternate lines. These refrains would have been sung by the dancers in time with the dance. Most northern and west European ballads are written in ballad stanzas or quatrains (four-line stanzas) of alternating lines of iambic tetrameter (eight syllables) and iambic trimeter (six syllables), known as ballad meter.

Ballads can be slow, mournful love songs, but they can also be silly, light poems. In popular music, the word ballad can also refer to a slow, romantic, or sentimental song. Ballads are perhaps the most ancient of all literary forms, and the earliest works of literature that we know of are all mythological epic poems that tell the stories of the culture that produced them.

Folk (or traditional) ballads are anonymous and recount tragic, comic, or heroic stories with emphasis on a central dramatic event. Beginning in the Renaissance, poets have adapted the conventions of the folk ballad for their own original compositions. English language ballads are typically composed of four-line stanzas that follow an ABCB rhyme scheme.

In summary, a ballad is a narrative poem that tells a story, often set to music, and can be either a traditional folk song or a literary composition.