1. One who contests the validity of a will, trust, or other legal instrument. — Also termed objectant; caveator.
2. Trademarks. One who challenges the placement of a trademark on the Principal Register. • The term refers to a challenger in (1) an interference proceeding, (2) an opposition proceeding before a mark is placed on the Principal Register, or (3) a cancellation proceeding after the mark is placed on the Principal Register. [Cases: Trade Regulation 217. C.J.S. Trade-Marks, Trade-Names, and Unfair Competition §§ 179, 183.]
3. Patents. A party to an interference proceeding in the U.S. Patent and Trademark Office. — Also termed (in sense 3) interferant. [Cases: Patents 106(1). C.J.S. Patents §§ 159–162, 165.]
