The Collaborative International Dictionary of English v.0.48:

Circulate \Cir"cu*late\, v. i. [imp. & p. p. Circulated; p.
   pr. & vb. n. Circulating.] [L. circulatus, p. p. of
   circulare, v. t., to surround, make round, circulari, v. i.,
   to gather into a circle. See Circle.]
   [1913 Webster]
   1. To move in a circle or circuitously; to move round and
      return to the same point; as, the blood circulates in the
      body. --Boyle.
      [1913 Webster]

   2. To pass from place to place, from person to person, or
      from hand to hand; to be diffused; as, money circulates; a
      story circulates.
      [1913 Webster]

   Circulating decimal. See Decimal.

   Circulating library, a library whose books are loaned to
      the public, usually at certain fixed rates.

   Circulating medium. See Medium.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Circulate \Cir"cu*late\, v. t.
   To cause to pass from place to place, or from person to
   person; to spread; as, to circulate a report; to circulate
   bills of credit.
   [1913 Webster]

   Circulating pump. See under Pump.

   Syn: To spread; diffuse; propagate; disseminate.
        [1913 Webster]

WordNet (r) 3.0 (2006):

circulate
    v 1: become widely known and passed on; "the rumor spread"; "the
         story went around in the office" [syn: go around,
         spread, circulate]
    2: cause to become widely known; "spread information";
       "circulate a rumor"; "broadcast the news" [syn: circulate,
       circularize, circularise, distribute, disseminate,
       propagate, broadcast, spread, diffuse, disperse,
       pass around]
    3: cause be distributed; "This letter is being circulated among
       the faculty" [syn: circulate, pass around, pass on,
       distribute]
    4: move through a space, circuit or system, returning to the
       starting point; "Blood circulates in my veins"; "The air here
       does not circulate"
    5: move in circles [syn: circle, circulate]
    6: cause to move in a circuit or system; "The fan circulates the
       air in the room"
    7: move around freely; "She circulates among royalty"
    8: cause to move around; "circulate a rumor" [syn: mobilize,
       mobilise, circulate]