A period of calm, dry, mild weather, with hazy atmosphere, occurring in the late autumn in the Northern United States. Also transf. in other countries.
(The name is generally attributed to the fact that the region in which the meteorological conditions in question were originally noticed was still occupied by the Indians; but other more specific explanations have been essayed. In its origin it appears to have had nothing to do with the glowing autumnal tints of the foliage, with which it is sometimes associated [...])