A brier is a thorny or prickly plant. The biblical term may refer to a thorn shrub used in hedges, a palm prickle, a thorny bush generally, or the land caltrop, a low plant with three-pronged spikes.
Briers and thorny shrubs symbolize desolation, barrenness, and troublesome people. The land caltrop is used in a comparison involving plants that cannot yield useful fruit.
The word translates several different Hebrew terms and does not designate one single botanical species. Some references have been associated with the nettle or the so-called apple of Sodom.