Source : Webster's Revised Unabridged Dictionary (1913)

Patronize \Pa"tron*ize\, v. t. [imp. & p. p. {Patronized}; p.
   pr. & vb. n. {Patronizing}.]
   1. To act as patron toward; to support; to countenance; to
      favor; to aid.

            The idea has been patronized by two States only.
                                                  --A. Hamilton.

   2. To trade with customarily; to frequent as a customer.
      [Commercial Cant]

   3. To assume the air of a patron, or of a superior and
      protector, toward; -- used in an unfavorable sense; as, to
      patronize one's equals.

Source : WordNet®

patronize
     v 1: assume sponsorship of [syn: {sponsor}, {patronise}]
     2: do one's shopping at; do business with; be a customer or
        client of [syn: {patronise}, {shop}, {shop at}, {buy at},
        {frequent}, {sponsor}] [ant: {boycott}, {boycott}]
     3: treat condescendingly [syn: {patronise}, {condescend}]
     4: 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: {patronise}, {patronage}, {support}, {keep
        going}]