The Collaborative International Dictionary of English v.0.48:

Patronage \Pa"tron*age\, n. [F. patronage. Cf. LL. patronaticum,
   and L. patronatus.]
   1. Special countenance or support; favor, encouragement, or
      aid, afforded to a person or a work; as, the patronage of
      letters; patronage given to an author.
      [1913 Webster]

   2. Business custom. [Commercial Cant]
      [1913 Webster]

   3. Guardianship, as of a saint; tutelary care. --Addison.
      [1913 Webster]

   4. The right of nomination to political office; also, the
      offices, contracts, honors, etc., which a public officer
      may bestow by favor.
      [1913 Webster]

   5. (Eng. Law) The right of presentation to church or
      ecclesiastical benefice; advowson. --Blackstone.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Patronage \Pa"tron*age\, v. t.
   To act as a patron of; to maintain; to defend. [Obs.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

patronage
    n 1: the act of providing approval and support; "his vigorous
         backing of the conservatives got him in trouble with
         progressives" [syn: backing, backup, championship,
         patronage]
    2: customers collectively; "they have an upper class clientele"
       [syn: clientele, patronage, business]
    3: a communication that indicates lack of respect by patronizing
       the recipient [syn: condescension, disdain, patronage]
    4: (politics) granting favors or giving contracts or making
       appointments to office in return for political support
    5: the business given to a commercial establishment by its
       customers; "even before noon there was a considerable
       patronage" [syn: trade, patronage]
    v 1: support by being a patron of
    2: be a regular customer or client of; "We patronize this
       store"; "Our sponsor kept our art studio going for as long as
       he could" [syn: patronize, patronise, patronage,
       support, keep going]

Moby Thesaurus II by Grady Ward, 1.0:

104 Moby Thesaurus words for "patronage":
   abetment, administration, advocacy, advocating, advocation, aegis,
   aid, auspices, backing, benefaction, bias, boosting, business,
   care, carriage trade, certificate of character, championship,
   character, character reference, charge, charity, clientage,
   clientele, condescension, contempt, contumely, countenance,
   credential, cure, custodianship, custody, custom, deigning,
   disdain, encouragement, favor, favoritism, favors of office,
   financing, fosterage, good name, goodwill, governance, government,
   guardianship, guidance, hands, help, humiliation, interest,
   jurisdiction, keeping, letter of introduction, management, market,
   melon, ministry, nepotism, oversight, partiality, pastorage,
   pastorate, pastorship, patronizing, plum, political patronage,
   pork, pork barrel, pork-barreling, preference, promotion,
   protection, protectorship, public, purchasing public, recommend,
   recommendation, reference, repute, rural market, safe hands, scorn,
   seconding, spoils system, sponsorship, stewardship, stooping,
   subsidy, suburban market, superiority, support, sympathy,
   testimonial, trade, trading, traffic, tutelage, voucher, ward,
   wardenship, wardship, watch and ward, wing, youth market



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

PATRONAGE. The right of appointing to office; as the patronage of the
president of the United States, if abused, may endanger the liberties of the
people.
     2. In the ecclesiastical law, it signifies the right of presentation to
a church or ecclesiastical benefice. 2 Bl. Com. 21.