This can get confusing, but it’s pretty simple once you wrap your head around it. Alexa refers to Amazon’s smart assistant. It’s the voice you talk to who can control your smart home, play music, and look up answers to your kid's homework questions. Echo refers to Amazon’s line of smart speakers and displays. It applies to the actual hardware. So, if you wanted to build an Amazon smart home, you’d buy Echo smart speakers and displays, which support the Alexa digital assistant.