Emily Dickinson Lexicon

SHACK, n.

In ancient customs of England, a liberty of winter pasturage. In Norfolk and Suffolk, the lord of a manor has shack, that is, liberty of feeding his sheep at pleasure on his tenants' lands during the six winter months. In Norfolk, shack extends to the common for hogs, in all men's grounds, from harvest to seed-time; whence to go a-shack is to feed at large. – Cowel. Encyc. In New England, shack is used in a somewhat similar sense for mast or the food of swine, and for feeding at large or in the forest, [for we have no manors,] and I have heard a shiftless fellow, a low itinerant beggar, a vagabond, called a shack.