'Perseverance': the meaning behind the name of Nasa's Mars robot

The Nasa robot that recently landed on Mars to search for signs of life is called Perseverance. It joins another rover named after a scientific virtue, Curiosity, which has been trundling around on the red planet since 2012. But why is perseverance necessarily a good thing?

The word comes, via French, from the Latin perseverare, the root of which, severus, simply means “severe”: the compound term thus means one who follows a path steadfastly without being waylaid or dismayed by difficulties. So in English since the 14th century, often with a sense of pious virtue: the angels sing in Milton’s Paradise Lost that the newly created race of humans are “happy, if they know / Their happiness, and persevere upright!”

We may assume that an extraterrestrial robot is not named for the special theological meaning (OED: “to continue until death in a state of grace”), but its handlers might hope it exemplifies another old sense – of remaining loyal, rather than going rogue in space. In the meantime you may irritate people by deliberately adopting the once-standard pronunciation “per-SEVerance”, and noting mildly that bad states of affairs can also be said to persevere, not excluding incompetent governments or plagues.

• Steven Poole’s A Word for Every Day of the Year is published by Quercus.