Egypt tombs suggest pyramids not built by slaves

[D B Campbell]

However, as you pointed out, 'doru' meant also 'spear'. In this example is about choosing one of several existing meanings, not adding a new meaning which the original word didn't have.

...No, you seem to have misunderstood, perhaps because English may not be your native tongue. 'Doru' does NOT literally mean 'spear' ... 'Doru', though not originally literally meaning 'spear', came to refer to spear - a new meaning for the word.

I'm afraid that it does actually mean "spear". Derivation and meaning are two separate issues.

You seem to have a peculiar view of the art of translating. No translator would describe a warrior brandishing a "floorboard", just because one of the meanings of doru happens to be a plank. Another of the meanings happens to be "spear", which is perfect in this context.

By your analogy, we would need to argue that one of the meanings of Aeguptioi was "slaves", which it manifestly is not. My literal translation of the Herodotus passage allows the intelligent reader to make his/her own judgement, whereas De Selincourt has overstepped his brief as translator by adding his own interpretation, which should properly be confined to a Commentary. The mere fact that we are arguing about this shows that he has failed to translate the passage accurately. At the very least, he should indicate which bits are original Herodotus and which bits are his own interpretation.