chiltern hundreds, [AS. Chiltern the Chiltern, high hills in Buckinghamshire, perh. Fr. ceald cold + ern, ærn, place.].
A tract of crown land in Buckinghamshire and Oxfordshire, England, to which is attached the nominal office of steward. As members of Parliament cannot resign, when they wish to go out they accept this stewardship, which legally vacates their seats. [1913 Webster]