what is an ad group in Google AdWords?

An ad group contains one or more ads which target a shared set of keywords.

Google adwords is an advertising system in which advertisers target few keywords to promote their clickable ads to appear in Google search results.

Google Adwords is a paid keyword promotion tool used to build your keyword popularity and also generate good traffic from them.

Google AdWords is Google's advertising product, which displays your ads to people looking for your products or services on Google or its partner sites.