I noticed that in Russian, when one wants to sell something in USD he writes instead in Cyrillic letters: у.е. for example: 120.000 у.е. What's the relation between the letters у.е. to USD?
2 Answers
У. е. means условная единица, "conventional unit".
States with significant Russian speaking population (Russia, Belarus, Ukraine, other former USSR republics) were experiencing high level of inflation and financial instability during the 90's and early 2000's, so the businesses usually kept their books of accounts and price lists in stable currencies like USD or the Deutsche Mark or later Euro, and only used the national currencies to actually convey financial transactions, at the rate in effect as of the moment of the transaction.
Listing the prices in currencies other than national, however, was illegal, so as a workaround, the prices were listed as "conventional units" and a remark was made that the conventional unit rate was the same as the USD or other stable currency rate. But the rate could really be anything, at the retailer's discretion, so it varied a lot and was used for marketing tactics.
So the у. е. is "conventional unit" which is usually one USD but can be off by several percent or something completely different altogether.
This can also be used as a metonymy for "the United States dollar"
“У.е.” is for “условные единицы”, “conditional unit”. IIRC the term originated because by law you couldn't set prices in foreign currencies, but what you could do is set a price in some unit that is convertible to rouble in a particular fashion. So, when a shop wanted to set a price in USD, they would say that the thing costs 100 “у.е.” with a disclaimer that one “у.е.” means the number of roubles for one USD.
See also: Russian Wiki.