What is "rock day"

Distaff \Dis"taff\, n.; pl. Distaffs, rarely Distaves. [OE. distaf, dysestafe, AS. distaef; cf. LG. diesse the bunch of flax on a distaff, and E. dizen. See Staff.]

1. The staff for holding a bunch of flax, tow, or wool, from which the thread is drawn in spinning by hand.

   I will the distaff hold; come thou and spin.
   --Fairfax.

2. Used as a symbol of the holder of a distaff; hence, a woman; women, collectively.

   His crown usurped, a distaff on the throne.
   --Dryden.

   Some say the crozier, some say the distaff was too busy.
   --Howell.

   Note: The plural is regular, but Distaves occurs in Beaumont & Fletcher.

   Descent by distaff, descent on the mother's side.

   Distaff Day, or Distaff's Day, the morrow of the Epiphany, that is, January 7, because working at the distaff was then resumed, after the Christmas festival; -- called also Rock Day, a distaff being called a rock.
   --Shipley.