Reading between the lines
As you stroll down to your court, you should see a regular rectangle divided in two by a net, which should be 3 feet high at its centre point if you want to check.
If your court is marked out with a pair of lines on its longest sides that create a tramline effect, then it is suitable for singles and doubles play. Singles players can simply ignore the outer set of lines, and doubles players should play to the widest lines, except for when they are serving, when the court uses the singles lines. A centre line divides the service boxes into left and right, and should also be marked on the baseline, behind which you stand to serve.
The lines are considered part of the court in tennis, so a ball that lands on a line is “in” – hence all that fuss about chalk dust at Wimbledon.