Source : Webster's Revised Unabridged Dictionary (1913)

Pan- \Pan-\, Panta- \Pan"ta-\, Panto- \Pan"to-\ [Gr. ?, m.,
   ?,neut., gen. ?, all.]
   Combining forms signifying all, every; as, panorama,
   pantheism, pantagraph, pantograph. Pan- becomes pam- before b
   or p, as pamprodactylous.