The Collaborative International Dictionary of English v.0.48:

Caravan \Car"a*van\ (k[a^]r"[.a]*v[a^]n or k[a^]r*[.a]*v[a^]n";
   277), n. [F. caravane (cf. Sp. caravana), fr. Per. karw[=a]n
   a caravan (in sense 1). Cf. Van a wagon.]
   1. A company of travelers, pilgrims, or merchants, organized
      and equipped for a long journey, or marching or traveling
      together, esp. through deserts and countries infested by
      robbers or hostile tribes, as in Asia or Africa.
      [1913 Webster]

   2. A large, covered wagon, or a train of such wagons, for
      conveying wild beasts, etc., for exhibition; an itinerant
      show, as of wild beasts.
      [1913 Webster]

   3. A covered vehicle for carrying passengers or for moving
      furniture, etc.; -- sometimes shorted into van.
      [1913 Webster]

WordNet (r) 3.0 (2006):

caravan
    n 1: a procession (of wagons or mules or camels) traveling
         together in single file; "we were part of a caravan of
         almost a thousand camels"; "they joined the wagon train for
         safety" [syn: caravan, train, wagon train]
    2: a camper equipped with living quarters [syn: van,
       caravan]
    v 1: travel in a caravan