Much of the following info is from The Volvo Owners Club.
When the decision was taken to start producing Volvo cars in August 1926, financial backer Svenska Kullagerfabriken – SKF – reactivated a company that had been idle since 1920 for the purpose. The name of that company was Volvo — formed in 1915 for the manufacture and marketing of bearings for the automotive industry.
The SKF management came up with the Volvo name. It was simple, and easy to pronounce in most places around the world with a minimal risk of spelling errors. It also held an immensely strong symbolic connection to the company’s entire operations.
“Volvere” is the infinitive form of the verb “roll” in Latin. In its first person singular form, the verb “volvere” becomes “volvo,” i.e. “I roll.” Its Latin form gives rise to several derivations of the word that in one way or another, and in many languages too, describe a rotating movement, for instance, revolver.
When Volvo was reactivated, the company adopted the ancient chemical symbol for iron — a circle with an arrow pointing diagonally upwards to the right.
This is one of the oldest and most common ideograms in Western culture and originally stood for the planet Mars in the Roman Empire. Because it also symbolised the Roman god of warfare, Mars, and the masculine gender (as every bird-watcher can tell), an early relationship was established between the Mars symbol and the metal from which most weapons were made at the time, iron.
As such, the ideogram has long been the symbol of the iron industry, not least in Sweden. The iron badge on the car was supposed to take up this symbolism and create associations with the honoured traditions of the Swedish iron industry: steel and strength with properties such as safety, quality and durability.