week [OE] An Old English word that is probably from a root meaning ‘sequence, series’. The seven-day week used in the Hebrew and then the Christian calendar corresponds to the biblical creation story, in which God created the universe in six days then rested on the seventh. The Romans, who adopted it in ad 321, would have brought this week over to Britain. ‘A week is a long time in politics’ was first said by Harold Wilson, the British Labour prime minister, at the time of the 1964 sterling crisis. See also tuesday.