a body of soldiers whose number differed at different times, and in the time of Augustus seems to have consisted of 6826 men (i.e. 6100 foot soldiers, and 726 horsemen)
derivation: of Latin origin
http://bible.crosswalk.com/Lexicons/Greek/grk.cgi?number=3003&version=kjv

Additional information:
Middle English legioun, from Old French legion, from Latin legi, legin-, from legere, to gather.

Additional acknowledgement:
The additional information was adapted from the derivation at
http://dictionary.reference.com/search?q=legion

Comment:
The word "legion" was used in paragraph 029-a which reads, "And Jesus asked him, saying, What is thy name? And he said, Legion many. And besought him that he would not send them out." The question was, "What is thy name?" That is, what is your purpose, your destiny, your goal? The answer, "Legion many", seems to make no sense until the word "legion" is replaced by its root meaning, "to gather". Then the answer reads, "To gather many."

A link to each occurrence of this word in the homepage:
1] legion