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

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "caravan":
   Conestoga wagon, camp trailer, camper, cavalcade, column, cortege,
   covered wagon, dray, dress parade, flyover, funeral, haywagon,
   house trailer, line, march past, mobile home, motorcade,
   mule train, pack train, parade, pomp, prairie schooner, procession,
   promenade, review, semitrailer, skimmington, stream, string,
   trail car, trailer, trailer camp, trailer court, trailer park,
   train, truck trailer, van, waggon, wagon, wain