Out-of-order execution is a term used in computer science to describe a technique that allows the processor to execute instructions in a sequence different from the order in which they were written in the program code. This technique can increase the efficiency of processor use by reducing idle time that arises when instructions are dependent on one another. There are several synonyms for out-of-order execution, including dynamic execution, speculative execution, and delayed execution. Dynamic execution emphasizes flexibility while speculative execution emphasizes the guesswork that might have to be done to execute instructions out of order. Delayed execution emphasizes the latency involved in waiting for instructions that might otherwise hold up the processor.