<Table> <Tr> <Td> </Td> <Td> Look up window of opportunity in Wiktionary, the free dictionary . </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> Look up window of opportunity in Wiktionary, the free dictionary . </Td> </Tr> <P> A window of opportunity (also called a margin of opportunity or critical window) is a period of time during which some action can be taken that will achieve a desired outcome . Once this period is over, or the "window has closed", the specified outcome is no longer possible . </P>

Where did the phrase window of opportunity come from