The former is Audi's language for the wagon bodytype, one that spells heritage for the marque. Think RS2 - the 'mother of lean and mean' was spawned with help from sportscar manufacturer Porsche.
The latter is short for 'Renn Sport', which simply means 'motorsport' in German. And so far, cars which are associated with racing have been exciting.
A quick glance at history revealed how these monikers conspired to become some of the world's most potent, yet subtle looking machines. Cloaked in some lightly spruced-up sheet metal, it takes the discerning to tell it apart from its benign cousins.
Since the RS2, Audi has been more than capable in churning out its own array of grocery hunters, with the RS6 reining the helm. The new flagship has been revealed late last year, and while we anticipate its arrival, we sample the next in line - the RS4 Avant.
Our test car came in Misano Red - one of the series of colours that pays tribute to famous racetracks around the globe (Daytona Grey, Sepang Blue etc). If it had came in any colour less striking, it would have been the perfect 'sleeper car' - blessed with high performance yet with an unassuming exterior.
That said, the usual hints are still present - bulging wheel arches, iconic twin-oval tail pipes, and most importantly the RS badges. Like clues to a puzzle, these little bits and pieces string up and point to the car's real identity.
The insides of the RS4 look largely familiar, especially to those acquainted with offerings from the Ingolstadt carmaker. Of course, it still gets the much needed extra bits to differentiate it from the less potent counterparts - red stitching, RS-badged gear lever and steering wheel, to name a few.
The flat-bottomed wheel is delightful to hold. And in true Audi fashion, bits and trims feel premium to touch. Equipments are well laid, and there is nothing to fault about ergonomics as well.
The wagon has enough space to be practical for a family of five - with additional boot space for loots too. The boot measures 490 litres, and is further expandable to 1,430 litres - figures which will put a smile on the family man.
The RS4 is like a doctor's prescription to speed - clinical and fast-acting. Bearing the RS moniker, the dosage is potent - 443bhp and 430Nm of torque - sufficient to make the century sprint take place in just 4.7 seconds.
The 4.2-litre powerplant gives a distinctive howl when pulled to the red line - music to the ears of any car fanatic. That said, outsiders (people on the streets or in the car next lane) will probably get a clearer note of it as the cabin insulation dulls a good part of the symphony.
All these, however, comes at a price - the RS4 will do 6.5km/L, although we reckon this will hardly cause a frown on its buyers.
The seven-speed S-tronic is faultless in dispatching the power to the wheels, acting decisively through the range and at times providing an intoxicating notch during gear shifts - akin to that from a manual cog box.
Equally potent is the quattro all-wheel drive. Even in spirited manoeuvres around bends, the car feels very planted, with rarely a slip of the wheel.
On the downside, while the steering feels weighted in the sportiest driving mode, it does without much feedback, which puts down on driving involvement.
Conclusion
Like the BMW M and Mercedes-Benz AMG, the RS is the cream-of-crop from Audi. However, it is the avant bodystyle of the RS4 which gives a distinctive character.
We love how the RS4 pieces together - it is effectively fast and, whilst at it, does good for the family man.
There are many choices for the well-heeled - but this could be one of the most complete.
