<Tr> <Td> Seaman </Td> <Td> Private or gunner or trooper </Td> <Td> Aircraftman or airman </Td> </Tr> <Tr> <Td_colspan="3"> Talk View </Td> </Tr> <P> A non-commissioned officer (NCO) is a military officer who has not earned a commission . Non-commissioned officers usually obtain their position of authority by promotion through the enlisted ranks . In contrast, commissioned officers hold higher ranks than NCOs, have more legal responsibilities, are paid more, and often have more non-military training such as a university diploma . Commissioned officers usually earn their commissions without having risen through the enlisted ranks . </P> <P> The NCO corps usually includes all grades of corporal and sergeant; in some countries, warrant officers also carry out the duties of NCOs . The naval equivalent includes some or all grades of petty officer . There are different classes of non-commissioned officer, including junior non-commissioned officers (JNCO) and senior (or staff) non-commissioned officers (SNCO). </P>

What does nco stand for in the military