What is the difference between Dogecoin and Dogechain?

Could you please clarify the distinction between Dogecoin and Dogechain for me? As I understand, both involve the concept of digital currency, but I'm unsure about the specific nuances that set them apart. Are they two separate entities or are they somehow interconnected? Additionally, how do they differ in terms of their purpose, technology, and adoption within the cryptocurrency space? Your insights would be greatly appreciated.