EIN is German for one. It can also stand for:

• Eindhoven Airport, an airport with IATA code EIN
• Endometrial intraepithelial neoplasia, a precancerous condition in women
• Employer Identification Number, a number assigned by the United States Internal Revenue Service to all employers
• Ein, a character in the anime series Cowboy Bebop
• Ein, see Hayate (Dead or Alive), a character in the video game Dead Or Alive
• Ein, the protagonist of the Game Boy Advance game Riviera: The Promised Land
• Ein (Hebrew, ???) means Nothing, Null. See also Ein Sof

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