Source : Webster's Revised Unabridged Dictionary (1913)

Earn \Earn\, v. t. [imp. & p. p. {Earned}; p. pr. & vb. n.
   {Earning}.] [AS. earnian; akin to OHG. arn?n to reap, aran
   harvest, G. ernte, Goth. asans harvest, asneis hireling, AS.
   esne; cf. Icel. ["o]nn working season, work.]
   1. To merit or deserve, as by labor or service; to do that
      which entitles one to (a reward, whether the reward is
      received or not).

            The high repute Which he through hazard huge must
            earn.                                 --Milton.

   2. To acquire by labor, service, or performance; to deserve
      and receive as compensation or wages; as, to earn a good
      living; to earn honors or laurels.

            I earn that [what] I eat.             --Shak.

            The bread I have earned by the hazard of my life or
            the sweat of my brow.                 --Burke.

   {Earned run} (Baseball), a run which is made without the
      assistance of errors on the opposing side.

   Syn: See {Obtain}.

Source : WordNet®

earned run
     n : a run that was not scored as the result of an error by the
         other team [ant: {unearned run}]