A liftglass is a rear windshield panel on an SUV, truck cap, or station wagon that is hinged separately from the main lower door or liftgate. It allows users to pop open just the glass section to drop small items into the cargo area or transport long objects like lumber without driving with the entire rear door open.
Heard on the job
Pop the liftglass so I can slide these two-by-fours in without tying down the whole hatch.