In England, this term designates a school in which such in-struction is given as will prepare the stu-dent to enter a college or university, and in this sense the phrase was used in the Massa-chusetts colonial act of 1647, requiring every town containing a hundred householders to set up a “grammar school.” See Jenkins v. Andover, 108 Mass. 97. But in modern Amer-lcan usage the term denotes a school, inter-mediate between the primary school and the high school, in which English grammar and other studies of that grade are taught
Source: Black’s Law Dictionary 2nd Ed (1910)
