Dictionary.com's Word of the Year is...
mid-14c., from Old French refraigner "restrain, repress, keep in check" (12c., Modern French Réfréner), from Latin refrenare "to bridle, hold in with a bit, check, curb, keep down, control," from re- "back" (see re-) + frenare "restrain, furnish with a bridle," from frenum "a bridle." Related: Refrained; refraining.
late 14c., from Old French refrain "chorus" (13c.), alteration of refrait, noun use of past participle of refraindre "repeat," also "break off," from Vulgar Latin *refrangere "break off," alteration of Latin refringere "break up, break open" (see refraction) by influence of frangere "to break." Influenced in French by cognate Provençal refranhar "singing of birds, refrain." The notion is of something that causes a song to "break off" then resume. OED says not common before 19c.
a phrase, line, or group of lines repeated at intervals throughout a poem, generally at the end of the stanza. Refrains are found in the ancient Egyptian Book of the Dead and are common in primitive tribal chants. They appear in literature as varied as ancient Hebrew, Greek, and Latin verse, popular ballads, and Renaissance and Romantic lyrics. Three common refrains are the chorus, recited by more than one person; the burden, in which a whole stanza is repeated; and the repetend, in which the words are repeated erratically throughout the poem. A refrain may be an exact repetition, or it may exhibit slight variations in meaning or form as in the following excerpt from "Jesse James": Jesse had a wife to mourn him all her life,The children they are brave.'Twas a dirty little coward shotMister Howard,And laid Jesse James in his grave.. . . . . . . .It was Robert Ford, the dirty little coward,I wonder how he does feel,For he ate of Jesse's bread and he slept inJesse's bed,Then he laid Jesse James in his grave.(Anonymous)