Definition of "pokeberry"

I said that ink made from pokeberries was better than that made from inkballs. I said that inkballs on oak trees were scarce. All the other students laughed. They bought commercial ink at the stores.

1975, Jesse Stuart, My world, page 8

considerin in her mind ... iffen the pleasure o gatherin some pokeberries an drawin dark purple picthures on a flat rock wi em would be worth the trouble...

2014, Lewis Carroll, Byron W. Sewell, Victoria J. Sewell, Alice's Adventures in an Appalachian Wonderland, Evertype, page 5