Maybe purple is more of a dark violet-ish color

They are technically the same thing. I believe the term "violet" is used almost exclusively when describing this color in terms of light (electromagnetic waves) whereas "purple" is used more to describe pigmentation such as with paints or dyes.

Maybe physicists possibly

What about car, automobile and/or vehicle?

They are technically the same thing. I believe the term "violet" is used almost exclusively when describing this color in terms of light (electromagnetic waves) whereas "purple" is used more to describe pigmentation such as with paints or dyes.