Recently, Apple's naming of its first foldable smartphone as "iPhone Duo" has sparked heated discussion.
Reportedly, "Duo" means "two" in both Latin and German, accurately capturing the foldable screen's "two-in-one" form factor. However, in the automotive world, this term was already written into technical history by Audi 36 years ago.
At the 1989 Frankfurt Motor Show, Audi unveiled the first-generation Audi Duo hybrid concept car, based on the 100 Avant.
The front wheels are driven by a 2.3-liter five-cylinder gasoline engine producing approximately 134 horsepower, while the rear wheels are powered by a 9 kW (about 12 hp) electric motor, with energy stored in nickel-cadmium batteries.
Audi proposed the dual-drive concept of "using fuel in the suburbs and electricity in the city," allowing drivers to freely switch between drive modes. This was considered ahead of its time in an era when hybrid technology was not yet widespread.
In 1996, Audi launched the third-generation Duo, based on the A4 Avant. It featured a 1.9-liter TDI diesel engine paired with a 20 kW electric motor and used lead-acid gel batteries, capable of reaching speeds up to 80 km/h in pure electric mode.
This was Audi's third hybrid model and its first hybrid product available for sale, priced at around 60,000 Deutsche Marks at the time.
On Apple's side, the word "Duo" also has historical roots. In 1992, Apple launched the PowerBook Duo series of laptops, positioned as ultra-thin and portable. The product codename was "BOB W" (Best Of Both Worlds), aiming to balance portability with desktop performance. The series remained on sale until 1997.