The term "summer lawn" can refer to two different things:

A lawn that is specifically designed to thrive in the summer months. This type of lawn would typically be made up of warm-season grasses that are tolerant of heat and drought.
The period of time during the summer when a lawn is most stressed. This is usually during the hottest and driest months, when the grass may go dormant or turn brown.

In the context of lawn care, summer lawn usually refers to the latter. This is the time of year when lawns need the most care and attention in order to stay healthy and green.

Here are some tips for keeping your summer lawn looking its best:

Water deeply and regularly, especially during hot, dry weather.
Mow regularly, but keep the blades high (2-3 inches).
Fertilize with a fertilizer that is specifically designed for summer lawns.
Control weeds and pests.
By following these tips, you can help your summer lawn stay healthy and green all season long.

Here are some additional information about summer lawns:

The best time to fertilize a summer lawn is in the early summer, before the heat of the season sets in.
If you live in an area with hot, dry summers, you may need to water your lawn more frequently than you would in other seasons.
Some common weeds that can be a problem in summer lawns include crabgrass, dandelions, and clover.
Some common pests that can damage summer lawns include grubs, chinch bugs, and armyworms.
With proper care, your summer lawn can stay healthy and green all season long.