In terms that are more common, we can refer eCommerce as the platform for buying and selling of products and services through business and services over internet. In a simplest form people use this term as online shopping. Both the terms means one and the same thing.
For your ecommerce store you are always on the lookout for ways and means to advertise your store. Thankfully there are a lot of tools and technologies that all you to promote your store but none better than Google AdWords.