The difference between steeping and brewing is as easy as whether or not there is continual heat applied to the immersed tea leaves.  Steeping involves the soaking of an item in a liquid, in this case, tea leaves in water, and that liquid can start out to be either cold, or hot. Brewing involves the continual application of heat from an outside source, like from a flame or burner. That is why beer and whiskey are "brewed" beverages, while tea is in fact, steeped.  And that's why brewing involves steeping, but steeping doesn't involve brewing.

Steeping and brewing tea are the key parts of the same process - making tea. Brewing is the actual act of making tea. On the other hand, steeping tea is the process that is involved. Brewing the best tasting cup of tea includes carefully steeping tea bags or loose tea leaves in heated water. Different types of teas have distinct steeping times and paying attention to this can make a huge difference. Steeping actually begins when you pour heated water over the tea. It's important to know that over-steeping can lead to bitterness. So, it's crucial to know the exact steeping temperatures and times for different types of teas.

Tea Steeping Guide

Black Teas - 208 degrees Fahrenheit (98 degrees Celsius) - 1-2 tsp/cup - 3-5 minutes

Green Teas - 175 degrees Fahrenheit (80 degrees Celsius) - 1-2 tsp/cup - 2-3 minutes

Oolong Teas - 195 degrees Fahrenheit (90 degrees Celsius) - 1-2 tsp/cup - 4-5 minutes

Herbal Teas - 212 degrees Fahrenheit (100 degrees Celsius) - 2-3 tsp/cup - 5-7 minutes

White Teas - 175 degrees Fahrenheit (80 degrees Celsius) - 1-2 tsp/cup - 2-3 minutes