A "suicide door" is the slang term for an automobile door hinged at its rear rather than the front. Such doors were originally used on horse-drawn carriages, but are rarely found on modern vehicles, primarily because of safety concerns.
Popularized in the custom car trade, the term is avoided by major automobile manufacturers in favor of alternatives such as "coach doors" (Rolls-Royce) [above], "FlexDoors" (Opel), "freestyle doors" (Mazda), "rear access doors" (Saturn), and "rear-hinged doors" (preferred technical term) Suicide doors were common on cars manufactured in the first half of the 20th century.
The nickname is mainly due to the design's propensity to seriously injure anyone exiting or entering the offside of the car if the door is hit by a passing vehicle. Also, in the era before seat belts, the accidental opening of such doors meant that there was a greater risk of falling out of the vehicle compared to front-hinged doors, where airflow pushed the doors closed rather than opening them further. Suicide doors were especially popular with mobsters in the gangster era of the 1930s, supposedly owing to the ease of pushing passengers out of moving vehicles, according to Dave Brownell, the former editor of Hemmings Motor News.More at Wikipedia. I've lost the source of the photos many years ago; I collected them after discovering the internet decades ago but before starting this blog, so didn't document the credits. Just cleaning out some old "Lincoln" material today.