wither, die, dry up, be seasoned
枯 centers on the loss of vitality and moisture: plants withering, things drying up, or life fading away. The sense of being seasoned extends this idea to something dried and matured, like aged wood or seasoned timber.
枯 combines 木 (tree) with 古, which likely contributes the sound and the idea of something old or dried up. A tree that is old and dry has withered.
An old (古) tree (木) that has lost its sap and stands withered and dry. Picture a gnarled, ancient tree with bare branches, completely dried up.
For コ, imagine a withered tree that has become so dry it's like a hard core (コア). The core of the old tree is all that remains: core -> コ.
drying up; running dry
to wither (of a plant); to be blasted; to die
dead leaf; dry leaves
to let dry; to kill (vegetation); to season (lumber)
dead tree; withered tree
cold wintry wind
traditional (Chinese or Japanese) dry landscape garden
withering; dying
ups and downs of life; vicissitudes of fortune
dry grass; dead grass; hay; withered grass
chestnut blight; chestnut canker
Dutch elm disease
thousands die to make one hero; one general reaches glory, ten thousand bones are left to dry
thousands die to make one hero; one general reaches glory, ten thousand bones are left to dry
to die at the top
completely drying up
withering of vegetation in winter; winter decay
to destroy; to kill off (trees)
scarcity of goods; being out of stock
to become hoarse