Meaning: Its source is Petros, a Greek name meaning "Rock."

Languages: This boy's name is used in Swedish.

Narrative: Petros, the source of Peter, was a Greek translation of Cephus the Aramaic nickname of one of Jesus' disciples. It was used to distinguish him from another disciple also named Simon, who was known as ''The Zealot.''

Simon the Rock became one of the founders of the Christian religion and, according to Roman Catholic tradition, the first Pope. These achievements, along with Jesus' pun on his name -- ''Upon this Rock I will build my church'' -- assured the evolution of this nickname into a primary name form.