What does “Box now” or “Box, box, box” mean?

The term BoxThe term Box comes from the German Boxenstopp, meaning pit stop and is used as a reference to the service... There's more... comes from the German Boxenstopp, meaning pit stop and is used as a reference to the service area outside the driver’s garageAn F1 garage is just that. A secure area for teams to set up their equipment and work on their... There's more....

‘Box’ is an instruction for the driverOK, so we all know what the driver is, right. I've always liked the description that F1 drivers are like... There's more... to come into the pitsThe Pits refers to the area immediately outside a team's garage where they are able to work on the car,... There's more... to receive new tyresToday's F1 cars are running 18-inch wheels (up from 13 inches in recent years) with the widths unchanged - 305mm... There's more..., a repair or an adjustment. 

The driver might receive a message such as “OK, box this lap” or a slightly more desperate “Box, box, boxA common use of the word Box is to use it three times in quick succession. This provides the driver... There's more...” if the driver is close to the pit entrance

There is a huge amount of data and noise distraction assaulting a driver as he pushes the car to its limits so short, clear and concise terms are favoured.