Nagini - naga is the Sanskrit word for snake and nag is the word meaning snake in several contemporary languages.

Nettle (Plant) - one of the ingredients of a potion for curing boils.

Nicholas Flamel - see Flamel, Nicholas

Niffler - the burrowing British niffler favors anything that glitters. Goblins often keep them to burrow deep underground for treasure.

Nogtail - a demon found in the rural regions of America, Europe and Russia. They look like stunted piglets with long legs, stubby little tails and narrow black eyes. They can creep into a sty to suckle from a sow with her own young. The longer it remains undetected, the longer the blight lasts on the farm it inhabits. The only way to be rid of it is to have a pure white dog chase it away beyond farm boundaries.

Norwegian Ridgeback (Dragons) - a dragon that closely resembles the Hungarian Horntail, except for prominent black back ridges rather than tail spikes. It is so aggressive to its own kind that it's one of the rarer types of dragon. The eggs are black and its young start breathing fire earlier than other breeds between one to three months of age. The ridgeback not only hunts land mammals, but unusual for a dragon, it also preys on water creatures.

Nox (Spell) - the spell that extinguishes light.

Numerology (Divination) - see Arithmancy (Divination)

Nundu - an east African beast, perhaps the most dangerous one in the world. The nundu is a giant leopard which moves in total silence. Its breath causes such disease as to kill entire villages. It has yet to be subdued by fewer than a hundred knowledgeable wizards working in unison.