A Push Lap is where a driverOK, so we all know what the driver is, right. I've always liked the description that F1 drivers are like... There's more... pushes his car as hard as he can prior to coming into the pits
The Pits refers to the area immediately outside a team's garage where they are able to work on the car,... There's more....
The rationale is that you are going to put on fresh tyresToday's F1 cars are running 18-inch wheels (up from 13 inches in recent years) with the widths unchanged - 305mm... There's more... so you can take everything out of the old ones before you change them, and when executed well, it can result in an undercut
The undercut is where you gain an advantage on the driver ahead by pitting before him and then maximising your... There's more... on the car ahead. Or, at the least, maintaining position.