A separation or opening between two of the concentric layers of timber. So Cup-shaken, Cup-shaky a. Cf. cup-defect (CUP sb. 13 d).
a. 1793. G. White, Observ. Vegetables, in Hist. Selborne, App. (1877), I. 421. The wood [chestnut] is very shakey, and towards the heart cup-shakey, that is to say apt to separate in round pieces like cups.
1807. Vancouver, Agric. Devon (1813), 286, note. Such of the yew as was not cup or wind shaken, was cut into plank.
1875. Laslett, Timber & Timber Trees, 31. The cup-shake…. This shake … is most frequently met with near the roots of trees.
