- nine day period
- nonobjective
- nonfigurative
- nondriver
- night letter
- Nymphaea stellata
- Nymphaea caerulea
- New Zealand honeysuckle
- necromantic
- new world porcupine
- nitrite
- necropneumonia
- nop instruction
- neurogenesis
- nicotine
- Norfolk terrier
- noggin
- nonfatal
- nodding groundsel
- north island edelweiss
- northern dune tansy
- niff
- nietzsche
- nitramine
- neon lamp
- neon tube
- number generator
- Napier's bones
- Napier's rods
- nephrolepis pectinata
- nephrolithiasis
- New York aster
- New England aster
- nonthermal
- Nerium oleander
- necessitarian
- northern holly fern
- Nephrolepis
- nucleoprotein
- nucleotidase
- nonlinear correlation
- not standard
- noncyclic
- New World anteater
- nit
- neurosurgical technique
- neurosurgeon
- noether
- nonsurgical
- next best