Source : Webster's Revised Unabridged Dictionary (1913)

Ebb \Ebb\, n. (Zo["o]l.)
   The European bunting.

Ebb \Ebb\, n. [AS. ebba; akin to Fries. ebba, D. eb, ebbe, Dan.
   & G. ebbe, Sw. ebb, cf. Goth. ibuks backward; prob. akin to
   E. even.]
   1. The reflux or flowing back of the tide; the return of the
      tidal wave toward the sea; -- opposed to {flood}; as, the
      boats will go out on the ebb.

            Thou shoreless flood which in thy ebb and flow
            Claspest the limits of morality!      --Shelley.

   2. The state or time of passing away; a falling from a better
      to a worse state; low state or condition; decline; decay.
      ``Our ebb of life.'' --Roscommon.

            Painting was then at its lowest ebb.  --Dryden.

   {Ebb and flow}, the alternate ebb and flood of the tide;
      often used figuratively.

            This alternation between unhealthy activity and
            depression, this ebb and flow of the industrial.
                                                  --A. T.
                                                  Hadley.

Ebb \Ebb\, v. i. [imp. & p. p. {Ebbed}; p. pr. & vb. n.
   {Ebbing}.] [AS. ebbian; akin to D. & G. ebben, Dan. ebbe. See
   2d {Ebb}.]
   1. To flow back; to return, as the water of a tide toward the
      ocean; -- opposed to {flow}.

            That Power who bids the ocean ebb and flow. --Pope.

   2. To return or fall back from a better to a worse state; to
      decline; to decay; to recede.

            The hours of life ebb fast.           --Blackmore.

   Syn: To recede; retire; withdraw; decay; decrease; wane;
        sink; lower.

Ebb \Ebb\, v. t.
   To cause to flow back. [Obs.] --Ford.

Ebb \Ebb\, a.
   Receding; going out; falling; shallow; low.

         The water there is otherwise very low and ebb.
                                                  --Holland.

Source : WordNet®

ebb
     n 1: a gradual decline (in size or strength or power or number)
          [syn: {ebbing}, {wane}]
     2: the outward flow of the tide [syn: {reflux}]

ebb
     v 1: flow back or recede; "the tides ebbed at noon" [syn: {ebb
          away}, {ebb down}, {ebb out}, {ebb off}] [ant: {tide}]
     2: hem in fish with stakes and nets so as to prevent them from
        going back into the sea with the ebb
     3: fall away or decline; "The patient's strength ebbed away"