To begin one’s education or career with; to mature. The analogy is to the emergence (“cutting” through the gums) of a baby’s teeth, which occurs during the first year of life. The earliest uses of this term involved not just plain teeth but eyeteeth; to cut one’s eyeteeth meant to gain experience. “There is no dealing with him without having one’s eyeteeth,” one J. J. Morier wrote in 1730. The eyeteeth, or upper canines, came to be so called because their nerves pass close to the eyes. By 1770 a book of American proverbs included “have his eyeteeth,” meaning to be mature, which probably came from the fact that the upper canines do not emerge until several other baby teeth have been cut. (See also give one's eyeteeth.) By 1860 the “eye” portion had been dropped and Charles Reade wrote, in his novel The Cloister and the Hearth, “He and I were born the same year, but he cut his teeth long before me.”