what is an nco in the army

A non-commissioned officer (NCO) is a military officer who does not hold a commission. Non-commissioned officers usually earn their position of authority by promotion through the enlisted ranks. The NCO corps usually includes many grades of enlisted, corporal and sergeant; in some countries, warrant officers also carry out the duties of NCOs. There are different classes of non-commissioned officers, including junior (lower ranked) non-commissioned officers (JNCO) and senior/staff (higher ranked) non-commissioned officers (SNCO) . NCOs are officially divided into two categories: junior non-commissioned officers, consisting of corporals/sailors first class and master corporals/master sailors; and senior non-commissioned officers, consisting of sergeants and petty officers 2nd class. NCOs are in charge of military training, discipline, practical leadership, role modeling, unit standards, and mentoring officers, especially juniors. Officers commanding platoons and above are assigned a chief or master sergeant, which is the units highest-ranking specialist, although chief and master sergeants are functions and not ranks in themselves. NCOs serving in the top three enlisted grades (E-7, E-8, and E-9) are termed senior non-commissioned officers.