The Collaborative International Dictionary of English v.0.48:

Pahlavi \Pah"la*vi\, Pahlevi \Pah"le*vi\, n.
   1. The language of Sassanian Persia. See Pehlevi.
      [1913 Webster]

   2. The script in which the Pahlavi language was written. It
      was taken from the Aramaic alphabet.
      [PJC]

   3. A gold coin formerly used in Iran, equal in value to 20
      rials.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Pehlevi \Peh"le*vi`\, n. [Parsee Pahlavi.]
   An ancient Persian dialect in which words were partly
   represented by their Semitic equivalents. It was in use from
   the 3d century (and perhaps earlier) to the middle of the 7th
   century, and later in religious writings. [Written also
   Pahlavi.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Persian \Per"sian\, n.
   1. A native or inhabitant of Persia.
      [1913 Webster]

   2. The language spoken in Persia. Ancient Persian of the 3rd
      to 10th centuries is also called Pahlavi, and modern
      Persian is also called Farsi.
      [1913 Webster + PJC]

   3. A thin silk fabric, used formerly for linings. --Beck.
      [1913 Webster]

   4. pl. (Arch.) See Persian columns, under Persian, a.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Pahlavi
    n 1: Shah of Iran who was deposed in 1979 by Islamic
         fundamentalists (1919-1980) [syn: Pahlavi, Mohammed Reza
         Pahlavi, Shah Pahlavi, Pahlevi, Mohammed Reza
         Pahlevi]
    2: the Iranian language of the Zoroastrian literature of the 3rd
       to 10th centuries [syn: Pahlavi, Pehlevi]
    3: the script (derived from the Aramaic alphabet) used to write
       the Pahlavi language