The two primary distinctions in our Army are:
-the existence of a Queen's Commission for officers. This is a document signed by the Governor General on behalf of HM The Queen that gives an officer the authority to exercise the power of command, to be loyal to the duly elected government, and to take care of the soldiers entrusted to his command (among other things). Non-commissioned Members (NCMs) include Warrant Officers(what some other Armies call various grades of Sergeants-Major), Non-Commissioned Officers (Master Corporals and Sergeants) as well as Corporals and Privates who are sometimes referred to as "Junior Ranks". None of these other rank groups have a Commission, hence the title "Non-Commissioned" although WOs have a "Warrant"; and
-the way in which the Army uses them. Officers are given the power of command by the law of Canada: most NCOs and WOs are not. (This is not to say that WOs/NCOs are not important: they are absolutely vital to any successful professional Army, and we are blessed with the best in the world. No Army unit can work properly without its WOs and NCOs, and smart Officers learn that early) Some Sergeants may be assigned command of a small team known as a "Section" "Detatchment" or "Crew" but these are normally the only WOs/NCOs who are given command. The usual role of the WO/NCO is in providing support to the chain of command (ie: the Officers above them) through their experience, technical knowledge, and common sense. They are also leaders in their own right, apart from officers, because they set an example to the junior ranks of soldierly skills and behaviour. For these reasons, WOs and NCOs are usually assigned duties involving the training of other soldiers, the maintenance of good order and discipline; and handling detailed technical and administrative matters. They are extremely important people. Although they are technically below all officers in rank, any officer who pays attention to his Basic Officer Training learns to listen to his WOs/NCOs. In the end the officer makes the decision, but he must consider what his WOs/NCOs have to say. As well, in our Army the WOs/NCOs have the particular duty to look after the welfare of the troops, which can be a challenge on a demanding mission.
Officers and WOs/NCOs have developed into their roles over several hundred years of warfare and military experience. At one time in past history Officers were usually of a higher social class and much higher education, while WOs/NCOs usually came from the poorer parts of society and often were only partly literate. Officers usually received their commisions because of their personal wealth and social status, but knew little or nothing about the technical side of soldiering. This vital knowledge was provided by the WOs/NCOs who came slowly up through the ranks, taking years to get promoted but gathering tons of experience. While officers still tend to have more formal education (but this is not universally true, especially in the Army Reserve where degreed WOs/NCOs are common) the social background distinction no longer holds true.
How's that for an answer? Cheers.