bur·dock (bûr?d?k?)n. Any of several plants of the genus Arctium of the composite family, having edible roots and pink or purplish flower heads surrounded by prickly bracts that form burs.[bur + dock.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.burdock (?b???d?k) n (Plants) a coarse weedy Eurasian plant of the genus Arctium, having large heart-shaped leaves, tiny purple flowers surrounded by hooked bristles, and burlike fruits: family Asteraceae (composites). Also called: hardoke [C16: from bur + dock4]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014bur?dock (?b?r d?k) n. a composite plant of the genus Arctium, esp. A. lappa, a coarse broad-leaved weed bearing prickly heads of burs that stick to clothing. [1590?1600; bur + dock4] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.