What is the difference between Crypto and altcoins?

In the realm of cryptocurrency and finance, it's crucial to understand the distinction between the overarching term 'Crypto' and the narrower concept of 'altcoins'. Could you elaborate on the key differences? When someone mentions Crypto, are they referring to Bitcoin specifically, or do they encompass the entire ecosystem of digital currencies? What role do altcoins play within this ecosystem? Do they offer unique functionalities or merely serve as alternatives to Bitcoin? Understanding these nuances is essential for investors and enthusiasts alike.