I know that Cantor set is nowhere dense and perfect. But if I have a nowhere dense perfect set, can I call it a Cantor set?
Also, I already proved that a certain subset of the real line is a nowhere dense perfect set. Knowing this, what else should I consider if I want to prove that its measure is zero?
Every nonempty totally disconnected perfect compact metric space is homeomorphic to the Cantor set (Wikipedia). On the real line, having empty interior implies being totally disconnected: indeed, every connected set is an interval, hence has nonempty interior.
For the second question: Cantor-type sets can have positive measure. To prove that the measure is zero, you need to find a way to cover it by intervals of total length $<\epsilon$, for any $\epsilon>0$.