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I don't think that's too common; Weisstein lists it as "Napier's Constant", but the main entry is under "e". Encyclopedia Britannica doesn't list "Napier's Constant" or "Napier's Constant" at all. Most people call it "base of the natural logarithm" I believe.
e is still called Euler's number in many texts too introductory to worry about confusion with γ - maybe that should be mentioned?