Start with what the Saab 9-3 is: a 3-/5-door hatchback / 2-door convertible with Petrol engine, built from 1998 to 2014, when airbags, anti-lock brakes and Japanese build quality became the world standard. What it meant takes a little longer. The shape is credited to Einar Hareide.
The background
The Saab 9-3 (pronounced nine-three) is a compact executive car initially developed and manufactured by the Swedish automaker Saab. The first generation 9-3 (1998–2003) is based on the GM2900 platform, changing to the GM Epsilon platform with the introduction of the second-generation car (2003–2012).
Other vehicles using this platform include the Opel Vectra, Chevrolet Malibu, and Cadillac BLS. National Electric Vehicle Sweden (NEVS), Saab's then parent company briefly assembled a few 9-3 sedans during 2013 and 2014.
The engineering
The engine is Petrol engine; other versions carried different engines, listed in the specification table below. Drive goes through a 5-speed manual / 4-speed automatic. The wheelbase is 2605 mm. These are manufacturer figures carried by Wikipedia and Wikidata, not road-test measurements.
Where it sits
In the Saab Automobile line-up the Saab 9-3 has a clear place: it replaced the Saab 900; it handed the line to the NEVS 9-3EV (Saab Electric Version); the factory was Trollhättan Assembly. The cars a buyer would have weighed it against include the Cadillac Escalade, the Audi TT, the Lexus IS. Its Saab Automobile stablemates include the Saab 60 and the Saab 600.
Saab 9-3 (YS3F) SportSedan 
Saab 9-3 Cabriolet 
Saab 9-3 Sport-Hatch 
Saab 9-3 SportHatch