I read in the New Yorker about people who make sound effects ‘in a large, retrofitted barn, painted baby blue’. It made me wonder again how people imagine retrofitting works. It seems to be the work of time-travellers. Do they think that refitting a barn now implies that a photo taken of it 50 years ago would show the new fittings?

Retro– signifies ‘backwards’. I am quite retro. I like looking at the past. My husband is almost entirely so. He lives in it.

Six centuries ago a child of ten was expected to understand what the retrograde movement of a planet entailed. A planet such as Mars appears to pause in its motion eastwards and loop in a contrary direction before resuming its eastward course.

Today we like to think the planets orbit the sun. The closest, Mercury, moves sometimes in its elliptical orbit more rapidly than it spins. From a point on its surface, the sun appears to begin rising, then sets before rising again. I tried to explain this to my husband by circling his armchair while turning round and round, but it didn’t help.

Retrograde began to be used metaphorically in a pejorative sense, with the virtuous opposite being progressive. That was how retrograde and progressive were used by Francis Bacon in the 17th century. Thomas Love Peacock, in Headlong Hall, had Mr Foster observe that the human mind ‘will necessarily become retrograde in ceasing to be progressive’.

Since the 1980s we have had available the term retronym, applied to things from the past to distinguish them from inventions not yet made. So we can call a 19th-century clock ‘analogue’ even though digital clocks were then unknown. Yet we happily use retro words for actions overtaken by newer technology and sail from New York on a screw-driven ship.

To me, retrofitting seems like postfitting, just as the addition of sound effects to films is part of post-production.