Answer 2: Enamel is the hard material that coats your teeth, and is made mostly of a mineral. However, we call other things enamel. There's enamel paint, which is totally different, and there's also porcelain enamel, which is used to make a lot of dishes.
All of this is due to Amazon's unique approach with the Echo. It's not a portable speaker like we've seen from Jambox and Logitech. Instead, it's a rather large, cylindrical device that needs to be plugged into power. It's something you'll likely just leave in a single spot in your home.
The Amazon Echo and Amazon Echo Dot are stationary devices (they need to be plugged in). The difference between them is that the Amazon Echo has a much better speaker built in, while the Dot is intended for use with an external speaker via line out/Bluetooth. The Dot is much smaller and cheaper so if you want Alexa in multiple locations, it's the best option.