la ortografía - spelling, orthography
  la oliva - olive
  ocasional - accidental, by chance, temporary,...
  la oruga - caterpillar
  oscuro - dark, obscure, overcast, uncertain,...
  el oro - gold
  la nevisca - snow flurry, light snowfall
  el neoyorquino, la neoyorquina - New Yorker, someone from New York
  el neonato, la neonata - newborn, neonate
  la necrología - obituary, obituary section of a...
  la noria - water wheel, Ferris wheel, big wheel...
  nulo - invalid, null and void
  el nudo - knot, junction or crossroads,...
  la ñame - yam
  Noruega - Norway
  la negrura - blackness, darkness
  la naranja - orange (the fruit or the color)
  el novelón - a long novel, often (although not...
  nipón, nipona - Japanese
  ñoño - dull, prudish, whiny, fussy,...