The Collaborative International Dictionary of English v.0.48:

Relegation \Rel`e*ga"tion\ (-g?"sh?n), n. [L. relegatio: cf. F.
   rel['e]gation.]
   The act of relegating, or the state of being relegated;
   removal; banishment; exile.
   [1913 Webster]

WordNet (r) 3.0 (2006):

relegation
    n 1: authorizing subordinates to make certain decisions [syn:
         delegating, delegation, relegating, relegation,
         deputation]
    2: the act of assigning (someone or something) to a particular
       class or category
    3: mild banishment; consignment to an inferior position; "he has
       been relegated to a post in Siberia"

Bouvier's Law Dictionary, Revised 6th Ed (1856):

RELEGATION, civil law. Among the Romans relegation was a banishment to a
certain place, and consequently was an interdiction of all places except the
one designated.
     2. It differed from deportation. (q.v.) Relegation and deportation
agree u these particulars: 1. Neither could be in a Roman city or province.
2. Neither caused the party punished to lose his liberty. Inst. 1,16, 2;
Digest, 48, 22, 4; Code, 9, 47,26.
     3. Relegation and deportation differed in this. 1. Because deportation
deprived of the right of citizenship, which was preserved notwithstanding
the relegation. 2. Because deportation was always perpetual, and relegation
was generally for a limited time. 3. Because deportation was always attended
with confiscation of property, although not mentioned in the sentence; while
a loss of property was not a consequence of relegation unless it was
perpetual, or made a part of the sentence. Inst. 1, 12, 1 & 2; Dig. 48, 20,
7, 5; Id. 48, 22, 1 to 7; Code, 9, 47, 8.