Source : Webster's Revised Unabridged Dictionary (1913)

Peepul tree \Pee"pul tree`\ [Hind. p[=i]pal, Skr. pippala.]
   (Bot.)
   A sacred tree ({Ficus religiosa}) of the Buddhists, a kind of
   fig tree which attains great size and venerable age. See {Bo
   tree}. [Written also {pippul tree}, and {pipal tree}.]

Bo tree \Bo" tree`\ (Bot.)
   The peepul tree; esp., the very ancient tree standing at
   Anurajahpoora in Ceylon, grown from a slip of the tree under
   which Gautama is said to have received the heavenly light and
   so to have become Buddha.

         The sacred bo tree of the Buddhists ({Ficus
         religiosa}), which is planted close to every temple,
         and attracts almost as much veneration as the status of
         the god himself. . . . It differs from the banyan
         ({Ficus Indica}) by sending down no roots from its
         branches.                                --Tennent.

Source : WordNet®

Ficus religiosa
     n : fig tree of India noted for great size and longevity; lacks
         the prop roots of the banyan; regarded as sacred by
         Buddhists [syn: {pipal}, {pipal tree}, {pipul}, {peepul},
          {sacred fig}, {bo tree}]