The Collaborative International Dictionary of English v.0.48:

Fabliau \Fa`bli`au"\, n.; pl. Fabliaux (-[-o]"). [F., fr.
   OF.fablel, dim. of fable a fable.] (Fr. Lit.)
   One of the metrical tales of the Trouv[`e]res, or early poets
   of the north of France.
   [1913 Webster]