Merriam-Webster's Collegiate® Dictionary, 11th Edition
BRIAR
I. noun also brier
Etymology: Middle English brere, from Old English brēr
Date: 15th century
a plant (as a rose, blackberry, or greenbrier) having a usually woody and thorny or prickly stem, briary adjective
II. noun
Etymology: short for briar pipe, from briar wood of the European heath, from French bruyère heath, from Middle French bruiere, from Vulgar Latin *brucaria, from Late Latin brucus heather, of Celtic origin; akin to Old Irish froech heather; akin to Greek ereikē heather
Date: 1882
a tobacco pipe made from the root or stem of a European heath ( Erica arborea )