潮的涨落,盛衰,消长

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.