To enter a contest; to become a candidate in an election. This expression comes from boxing, where in the early nineteenth century the practice of throwing one’s hat into the ring indicated a challenge. “Throw in his hat, and with a spring get gallantly within the ring,” wrote John Hamilton Reynolds (The Fancy, 1820). Later the term was transferred to other kinds of challenge, particularly political ones. It was so used by Theodore Roosevelt in 1912, when he told a journalist, “My hat’s in the ring,” indicating his candidacy.