The Collaborative International Dictionary of English v.0.48:

Running \Run"ning\, a.
   1. Moving or advancing by running. Specifically, of a horse:
      (a) Having a running gait; not a trotter or pacer.
      (b) trained and kept for running races; as, a running
          horse. --Law.
          [1913 Webster]

   2. Successive; one following the other without break or
      intervention; -- said of periods of time; as, to be away
      two days running; to sow land two years running.
      [1913 Webster]

   3. Flowing; easy; cursive; as, a running hand.
      [1913 Webster]

   4. Continuous; keeping along step by step; as, he stated the
      facts with a running explanation. "A running conquest."
      --Milton.
      [1913 Webster]

            What are art and science if not a running commentary
            on Nature?                            --Hare.
      [1913 Webster]

   5. (Bot.) Extending by a slender climbing or trailing stem;
      as, a running vine.
      [1913 Webster]

   6. (Med.) Discharging pus; as, a running sore.
      [1913 Webster]

   Running block (Mech.), a block in an arrangement of pulleys
      which rises or sinks with the weight which is raised or
      lowered.

   Running board, a narrow platform extending along the side
      of a locomotive.
      [1913 Webster]

WordNet (r) 3.0 (2006):

running board
    n 1: a narrow footboard serving as a step beneath the doors of
         some old cars