It's a place you can find on Italian highways where you can stop and do some (or all) of the following:
• Eat (sweet or savory snacks, sandwiches)
• Drink (water and drinks available. Alcohol as well)
• Buy souvenirs
• Buy toys
• Use the restroom (you'll find them as "Toilette")
Also:
• Get gas for your car
• Walk and move your legs during a long roadtrip
You can also find random stuff like clothes or electronics at an Autogrill, according to the size of it.
Do you have Autogrill or similar in your country?