| | NKMA | | No Known Medication Allergies |
| | NKOTB | | new kid on the block |
| | NKOTB | | New Kids On The Block |
| | nlaghitm | | never look a gift horse in the mouth |
| | NLB | | nonlinear behavior |
| | NLOS | | near line of sight |
| | NLSR | | Natural Language Speech Recognition |
| | nlt | | no later than |
| | nmbff | | not my best friend forever |
| | NMHJC | | Not Much Here, Just Chilling |
| | NMHJC | | Nothing Much Here Just Chilling |
| | nmw | | no matter what |
| | nmw | | non metallic wet underground |
| | NNM | | Network Node Manager |
| | NNN | | No New News |
| | NNN | | No No No |
| | nnpw | | new never played with |
| | NNSTDLTBBB | | Night Night Sleep Tight Don't Let the Bed Bugs Bite |
| | nntp | | Net News Transfer Protocol |
| | nntp | | Network News Transfer Protocol |
| | nntr | | no need to read |
| | nntr | | no need to reply |
| | NOBR | | no break |
| | NOFR | | Notice of Final Rulemaking |
| | noib | | Notice of Intent to Bid |
| | nomb | | none of my business |
| | nop | | no operation |
| | nop | | normal operating procedure |
| | NOPAT | | Net Operating Profit After Tax |
| | NORAD | | North American Aerospace Defense |
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