also noncom, by 1817, short for non-commissioned(officer).

The "non-coms" — non-commissioned, meaning, not non compos; though evil-minded high privates declare it might well mean that — have assigned to them an upper cabin, with staterooms, over the quarters of the officers, in the after-part of the ship. [James K. Hosmer, "The Color-Guard," Boston, 1864]

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