In http://www.straightdope.com/classics/a980508.html Cecil proposes several possible origins for the name of the Oreo cookie:
For the record, the main theories are: (1) Oreo was euphonious and easy to pronounce. (2) Oreo was inspired by the French word for gold, or, a color used on early package designs. (3) The name comes from the Greek word for mountain, oreo, and was chosen because the first test cookies were hill shaped. (4) An O-RE-O consists of c-RE-am between two O-shaped wafers.
Here are my comments on each of the theories:
Theory (1) This doesn’t really explain anything. Even if we agree that the word “Oreo” is particularly melodious – which I’m not altogether certain it is – the question simply becomes why did they choose THIS particular euphonious word?
Theory (2) It’s a bit of a stretch to get from OR to OREO. Given that they wanted to give the cookie a French name, where did the extra 2 syllables come from?
Theory (4) This is an acronym etymology. These are almost always wrong and this one is doesn’t even make much sense. Why use the letters “RE” to stand for “cream”? They could have just as easily used the letters “CR” and called the cookies OCROs.
Theory (3) Of the four ideas proposed, this one comes closest. But there is a problem. The modern Greek word for mountain is actually “voono”, not “oreo”. The ancient Greek word for mountain , “oros”, is closer but still troublingly different. Besides, the whole idea that the cookies were named for a mountain because the test cookies looked like mountains sounds a bit contrived.
If the cookies were given a Greek name – and I think they were – it has nothing to do with mountains or hills. “Oreo” is the modern Greek word for “Beautiful”.