The Collaborative International Dictionary of English v.0.48:

Jerusalem \Je*ru"sa*lem\ (j[-e]*r[udd]"s[.a]*l[e^]m), n. [Gr.
   'Ieroysalh`m, fr. Heb. Y[e^]r[=u]sh[=a]laim.]
   The chief city of Palestine, intimately associated with the
   glory of the Jewish nation, and the life and death of Jesus
   Christ.
   [1913 Webster]

   Jerusalem artichoke [Perh. a corrupt. of It. girasole i.e.,
      sunflower, or turnsole. See Gyre, Solar.] (Bot.)
   (a) An American plant, a perennial species of sunflower
       (Helianthus tuberosus), whose tubers are sometimes used
       as food.
   (b) One of the tubers themselves.

   Jerusalem cherry (Bot.), the popular name of either of two
      species of Solanum (Solanum Pseudo-capsicum and
      Solanum capsicastrum), cultivated as ornamental house
      plants. They bear bright red berries of about the size of
      cherries.

   Jerusalem oak (Bot.), an aromatic goosefoot (Chenopodium
      Botrys), common about houses and along roadsides.

   Jerusalem sage (Bot.), a perennial herb of the Mint family
      (Phlomis tuberosa).

   Jerusalem thorn (Bot.), a spiny, leguminous tree
      (Parkinsonia aculeata), widely dispersed in warm
      countries, and used for hedges.

   The New Jerusalem, Heaven; the Celestial City.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Synanthrose \Syn*an"throse"\ (s[i^]n*[a^]n"thr[=o]s), n. [From
   NL. Synantherae the Compositae; Gr. sy`n with + 'anqh`ros
   blooming.] (Chem.)
   A variety of sugar, isomeric with sucrose, found in the
   tubers of the Jerusalem artichoke (Helianthus tuberosus),
   in the dahlia, and other Compositae.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Helianthus tuberosus
    n 1: tall perennial with hairy stems and leaves; widely
         cultivated for its large irregular edible tubers [syn:
         Jerusalem artichoke, girasol, Jerusalem artichoke
         sunflower, Helianthus tuberosus]