Which came first, cake or pyramid?

News that Egypt's pyramids are to be scanned by radiation brings to mind an odd suggestion about where the word came from.

We get both "pyramid" and "obelisk" from Greek, in which obelisk also means skewer, and pyramid can be a kind of bun or cake, probably made of wheat flour and honey.

So it is sometimes said that Greek visitors named these grand Egyptian monuments in fun, like London's Gherkin and Cheese-grater, after familiar little items.

This is certainly true for obelisk. It has an excellent pedigree as a Greek word quite independent of Egypt.

Obelos ("roasting-spit") is in Homer's Iliad, and both it and obeliskos ("little spit") were used as names for money.

The historian Herodotus wrote of Egypt's monumental obeloi lithinoi (stone spits) in the 5th century BC.

The playwright Aristophanes wrote of thrushes roasted on obeliskoi, and the historian Diodorus used the term obeliskos for Egyptian monuments in the first century BC.

For "pyramid" it is the other way round.

A surviving fragment of a play by the Athenian comic poet Ephippus lists "pyramides" among a selection of after-dinner dainties, including sesame and hemp seed, milk, honey, cheese, and something called Zeus's brain.

The word may possibly be linked to the Greek words pyr "fire", pyrame (fire-shovel) or pyros (wheat flour).

But Ephippus was writing a century after Herodotus - who used "pyramides" to mean the monuments, not food.

So Ephippus' "pyramides" could just be named after what would have been a familiar shape to the peoples of the eastern Mediterranean.

If that is so, claiming that Egypt's pyramids were named after the food would be like saying fingers are so called because they look like sticks of fish meat.

Yet there is no alternative explanation for the name. There are geometrical puzzles in an Egyptian document called the Rhind Mathematical Papyrus which call the height of a pyramid "pr-m-ws" which may literally mean "go up from the crack".

But the papyrus was written 1,000 years before Herodotus, and there is no reason to think the term ever meant the pyramids themselves.

The usual Egyptian word for a pyramid is mr or mer. In hieroglyphics it is generally written with an owl (m) and a mouth (r) and a sign denoting the thing itself, which is much sharper than the pyramids we know.

Rather like some sort of cake, in fact.