Final thought from me - I was thinking about your post and it is indeed difficult to discern science from engineering. One dichotomy that occurred to me (which may not hold under close scrutiny) is that scientists are interested in _the pursuit of truth_, whereas engineers are interested in _building things_.
Overall I think it comes down to popular opinion, which can be fuzzy and doesn't apply the same rules to everyone. If enough people say someone is a dancer, then they are a dancer, even if they suck and don't dance that much. This applies to basically all titles that cross institution boundaries. Another great example is countries. Popular opinion determines which organizations are countries, not a strict definition. For example the EU vs places like Iceland or San Marino. [1]
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If not, does your definition of scientist require something other than doing work using the scientific method? Perhaps some specific quantity of work?
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[1] One of his companies, Armadillo Aerospace, was pretty much just a series of scientifc experiments. https://en.wikipedia.org/wiki/Armadillo_Aerospace