"greenbriers" in the noun sense
1. bullbrier, greenbrier, catbrier, horse brier, horse-brier, brier, briar, Smilax rotundifolia
a very prickly woody vine of the eastern United States growing in tangled masses having tough round stems with shiny leathery leaves and small greenish flowers followed by clusters of inedible shiny black berries
Source: WordNet® (An amazing lexical database of English)
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