Word Study
greening
CIDE DICTIONARY
greening, n.
A greenish apple, of several varieties, among which the Rhode Island greening is the best known for its fine-grained acid flesh and its excellent keeping quality. [1913 Webster]
OXFORD DICTIONARY
greening, n. a variety of apple that is green when ripe.
Etymology
prob. f. MDu. groeninc (as GREEN)
For further exploring for "greening" in Webster Dictionary Online