The symbol USDIRR.FOREX likely refers to the United States Dollar Interest Rate Return on the Forex market. This isn't a standard, widely recognized financial product or instrument traded on exchanges. Instead, it most likely represents a custom-defined data series or calculation used by a specific financial institution or trading platform. It would involve tracking the interest rate differential between the USD and another currency, potentially factoring in the spot and forward rates of the associated currency pair (e.g., EUR/USD, GBP/USD) to quantify the potential return from holding a position in the foreign currency based on interest rate dynamics. The precise calculation and interpretation of this symbol would be dependent on the specific context in which it is used, requiring a deeper understanding of its definition by the provider who created it.