What is "riding rhyme"

Riding \Rid"ing\, a.

1. Employed to travel; traveling; as, a riding clerk. ``One riding apparitor.''
   --Ayliffe.

2. Used for riding on; as, a riding horse.

3. Used for riding, or when riding; devoted to riding; as, a riding whip; a riding habit; a riding day. Riding clerk.

   1. A clerk who traveled for a commercial house. [Obs. Eng.]

   2. One of the ``six clerks'' formerly attached to the English Court of Chancery. Riding hood.

      1. A hood formerly worn by women when riding.

      2. A kind of cloak with a hood.

         Riding master, an instructor in horsemanship.

         Riding rhyme (Pros.), the meter of five accents, with couplet rhyme; -- probably so called from the mounted pilgrims described in the Canterbury Tales.
         --Dr. Guest.

         Riding school, a school or place where the art of riding is taught.

Riding rhyme is an early form of heroic verse. It has been described variously as a couplet rhyme, in five accents, and as a decasyllabic couplet. It is derived from the rhythm of the poetry in parts of Chaucer's Canterbury Tales depicting the pilgrims as they rode along.

Other examples might be Browning's " How they Brought the Good News From Ghent To Aix", or W. H. Audens verses for " Night Mail".