exponential function - Intuitive Understanding of the constant "$e$"

Potentially related-questions, shown before posting, didn't have anything like this, so I apologize in advance if this is a duplicate.

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I know there are many ways of calculating (or should I say "ending up at") the constant e. How would you explain e concisely?

It's a rather beautiful number, but when friends have asked me "what is e?" I'm usually at a loss for words -- I always figured the math explains it, but I would really like to know how others conceptualize it, especially in common-language (say, "English").

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related but not the same: Could you explain why $\frac{d}{dx} e^x = e^x$ "intuitively"?