1. Mediterranean annual or biennial herb having pinkish to purple flowers surrounded by spine-tipped scales; naturalized in America
   - star-thistle, caltrop

Type of: centaury

• United States Trade Representative
• United States Treasury
• United States Virgin Islands
• United States waters
• unitedly
• uniting
• unitisation
• unitise
• unitive
• unitization
• unitize
• unity
• univalent
• univalve
• univariate
• universal
• universal agent
• universal donor
• universal gas constant
• universal gravitational constant
• universal joint
• Universal Product Code
• universal proposition
• universal quantifier
• universal resource locator