The Collaborative International Dictionary of English v.0.48:

Puffball \Puff"ball`\, n. (Bot.)
   A kind of ball-shaped fungus (Lycoperdon giganteum, and
   other species of the same genus) full of dustlike spores when
   ripe; -- called also bullfist, bullfice, puckfist,
   puff, and puffin.
   [1913 Webster]

WordNet (r) 3.0 (2006):

puffball
    n 1: any of various fungi of the family Lycoperdaceae whose
         round fruiting body discharges a cloud of spores when
         mature [syn: puffball, true puffball]
    2: any of various fungi of the genus Scleroderma having hard-
       skinned subterranean fruiting bodies resembling truffles
       [syn: earthball, false truffle, puffball, hard-skinned
       puffball]

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "puffball":
   algae, autophyte, bean, bracken, brown algae, climber, conferva,
   confervoid, creeper, diatom, fern, fruits and vegetables, fucus,
   fungus, grapevine, green algae, gulfweed, herb, heterophyte, ivy,
   kelp, legume, lentil, liana, lichen, liverwort, mold, moss,
   mushroom, parasite, parasitic plant, pea, perthophyte,
   phytoplankton, planktonic algae, plant families, pulse, red algae,
   rockweed, rust, saprophyte, sargasso, sargassum, sea lentil,
   sea moss, sea wrack, seaweed, smut, succulent, toadstool, vetch,
   vine, wort, wrack