The phrase "recline angle" refers to the angle at which something, like a chair or seat, can be adjusted or tilted backward for a more comfortable and relaxed position. Full definition
Quad - zone climate control, heating and cooling seats, seat massage settings, recline angle of the rear zero gravity seats, just to name a few. (bgr.com)
Using the indicator, you should be able to find a comfortable recline angle for your child. (bestcarseathub.com)
Its lush foam padding and 3 point reclining angle provides a comfortable seating for your child. (babyseats.reviews)