I do my best to stay away from fast food when I am in China, but fate struck one night when, delayed by seven hours and landing in Xi’an without any luggage, I was obliged to find food for my family at two o’clock in the morning. Only one place was guaranteed to be open, and that was the Yangyang International Plaza McDonald’s, manned by sleepy staff facing a lone parent who had never been inside a Chinese burger bar before.

Here’s the problem with Mandarin: move an inch outside your specialty, and there is no guarantee that any of the words you see will mean anything to you. I had been speaking Chinese for twenty years, and was in town to give a lecture about medieval history, but the strange sigils describing arcane translation nightmares, like McFlurry and McNugget, might as well have been in Martian.

But I could talk my way around it in Chinese, in much the same way that a mad professor might forget the word for “dog”, but could tell you that it was a canine, and that if one was in a bun it was a hot one.

“What’s that thing called,” I began wearily, “which is very big, probably the biggest thing that you have, and there are two all-beef patties, special sauce, lettuce, cheese, pickles and onions, all in a sesame seed bun?”

“Ah,” said the bespectacled youth before me, “you are referring to the Immense Tyrant Without Compare (巨无霸).”

At last, a new use for the archaic term for a Bronze Age overlord, now recognised by twenty-first-century Chinese teenagers as the word for a Big Mac.

“All right, then,” I said. “Two Immense Tyrants Without Compare, and some fries.”

In case you were wondering, a McFlurry is a Wheat Whirlwind (mai xuanfeng), the Mai being the first syllable of McDonald’s in Chinese. A McNugget is a Wheat Gram Chicken Piece (maidang ji kuai), combining the first two syllables of McDonald’s in Chinese with a term I had last seen used for fragments of oracle bone. But not in Cantonese, where it’s a Wheat Happy Chicken (mak lok gai).

Jonathan Clements is the author of The Emperor’s Feast: A History of China in Twelve Meals.