A-pillar

noun

A-pil·lar ˈā-ˈpi-lər

variants or less commonly A-post

ˈā-ˈpōst

plural A-pillars also A-posts

: either one of two support posts that are positioned on either side of the windshield of a vehicle and connect the roof to the body

Changing the A-pillars meant that additional changes would ripple into the roof and the windshield, into the doors and door glass, into the fenders, into the hood.—

James Schefter, All Corvettes Are Red, 1998

also : a structural part of a vehicle that extends from the roof to the floorboard and that connects the windshield and front door to the body of the vehicle

Raise or lower the door hinges on the A-pillar until the door is the correct height. —

Mike Allen, Popular Mechanics, November 1998