Six Counties the counties of Northern Ireland, Antrim, Armagh, Down, Londonderry, Tyrone, and Fermanagh, which by the Treaty of 1920 were constituted as a separate province.
Six Day War a war, 5 –10 June 1967, in which Israel occupied Sinai, the Old City of Jerusalem, the West Bank, and the Golan Heights and defeated an Egyptian, Jordanian, and Syrian alliance. Arab name June War.
six hours' sleep for a man, seven for a woman, and eight for a fool proverbial saying, early 17th century, implying that the more sleep a person needs, the less vigorous and effective they are likely to be. (In the late 20th century, it was widely reported that Margaret Thatcher when British Prime Minister habitually slept for only four hours a night.)
six of one and half a dozen of the other a traditional saying, mid 19th century; meaning that there is little or nothing to choose between two sides.
See also deep-six, hit someone for six, sixes.