The Collaborative International Dictionary of English v.0.48:

Recession \Re*ces"sion\ (r[-e]*s[e^]sh"[u^]n), n. [L. recessio,
   fr. recedere, recessum. See Recede.]
   1. The act of receding or withdrawing, as from a place, a
      claim, or a demand. --South.
      [1913 Webster]

            Mercy may rejoice upon the recessions of justice.
                                                  --Jer. Taylor.
      [1913 Webster]

   2. (Economics) A period during which economic activity, as
      measured by gross domestic product, declines for at least
      two quarters in a row in a specific country. If the
      decline is severe and long, such as greater than ten
      percent, it may be termed a depression.
      [PJC]

   3. A procession in which people leave a ceremony, such as at
      a religious service.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Recession \Re*ces"sion\, n. [Pref. re- + cession.]
   The act of ceding back; restoration; repeated cession; as,
   the recession of conquered territory to its former sovereign.
   [1913 Webster]

WordNet (r) 3.0 (2006):

recession
    n 1: the state of the economy declines; a widespread decline in
         the GDP and employment and trade lasting from six months to
         a year
    2: a small concavity [syn: recess, recession, niche,
       corner]
    3: the withdrawal of the clergy and choir from the chancel to
       the vestry at the end of a church service [syn: recession,
       recessional]
    4: the act of ceding back [syn: recession, ceding back]
    5: the act of becoming more distant [syn: receding,
       recession]