Definition of eight-day:
(n) :
The digit/figure 8.
(n) :
(playing cards) Any of the four cards in a normal deck with the value eight.
(n) :
Eight o'clock.
(n) :
(rowing) The eight people who crew a rowing-boat.
(n) :
(nautical) A light, narrow rowing boat, especially one used in competitive rowing, steered by a cox, in which eight rowers each have two oars.
(n) :
(rowing, especially in plural) A race in which such craft participate.