Tennis can be played casually or competitive if you want. You can learn and understand the sport while you're are having fun.
Hitting a few shots in a row is called a rally.
This is a diagram of a tennis court:
Image source: http://www.allstaractivities.com/sports/tennis/Tennis-Terminology.htm
Its important to learn the terminology used in tennis and get to know the rules and scoring.
Ten Things All Kids Should Know About Tennis!
Some terminology is:
Volley, Serve, Ready position, Match, Love, Lob, Ground Stroke, Game, Forehand stroke (Hip height), Drop Shot, Down The Line, Doubles, Double Fault, Deuce, Cross-Court, Backhand stroke (Knee height), Alley, Advantage, Ace...
You can read more about tennis terms here http://www.allstaractivities.com/sports/tennis/Tennis-Terminology.htm and here http://en.wikipedia.org/wiki/Glossary_of_tennis_terms
Look here to learn about tennis rules http://westlake.k12.oh.us/hilliard/whspe/tennis/tennis_rules.htm and here for equipment http://news.bbc.co.uk/sport1/hi/tennis/rules_and_equipment/4223756.stm
You can read more about tennis terms here http://www.allstaractivities.com/sports/tennis/Tennis-Terminology.htm and here http://en.wikipedia.org/wiki/Glossary_of_tennis_terms
Look here to learn about tennis rules http://westlake.k12.oh.us/hilliard/whspe/tennis/tennis_rules.htm and here for equipment http://news.bbc.co.uk/sport1/hi/tennis/rules_and_equipment/4223756.stm
I want to learn more so we decided to look at what was on youtube.
Here is a funny song that was made about a famous tennis player in the 1980's who used to throw tantrums on court...
DID YOU KNOW..
long ago woman used to have to wear frilly panties like this, when they were playing tennis...

LOVE 15-30-40 -GAME-SET-MATCH