The M nonimmigrant visa category is for foreign nationals coming to the United States to take part in an established vocational or other recognized nonacademic institution, other than in language training programs. Specifically, the M nonimmigrant visa category is for:
(i) an alien having a residence in a foreign country which he has no intention of abandoning who seeks to enter the United States temporarily and solely for the purpose of pursuing a full course of study at an established vocational or other recognized nonacademic institution (other than in a language training program) in the United States particularly designated by him [her] and approved by the Attorney General, after consultation with the Secretary of Education, which institution shall have agreed to report to the Attorney general the termination of attendance of each nonimmigrant nonacademic student and if any such institution fails to make reports promptly the approval shall be withdrawn, and
(ii) the alien spouse and minor children of any such alien if accompanying him or following to join him. INA Section 101(a)(15)(M), 8 USC 1101(a)(15)(M).
The M nonimmigrant visa regulations are similar to those of the F nonimmigrant visa category and may be found at 8 CFR Sec. 214.2(m)(1) et. seq.