Daily Prophet - Wizarding world newspaper which keeps up to date with current events. One known reporter for the Daily Prophet is Rita Skeeter. It can be delivered to you through owl mail for 5 knuts.

Decree for the Reasonable Restriction of Underage Sorcery (1875) - Means that witches and wizards under 17 cannot practice magic outside of school unless a life is at stake. Any magic performed by an underage witch or wizard is detected by the Ministry because of The Trace.

Defence Against the Dark Arts - Subject taught at Hogwarts. Students learn to protect themselves from magical creatures and learn defensive and offensive spells. Sometimes written as DADA.

Deluminator - Device used to remove light from bulbs, lamps etc. The light can be returned if the deluminator is clicked again.

Diagon Alley - Street of wizarding shops located in London behind the Leaky Cauldron. It is completely hidden from the muggle world. 

Draconifors - Draconifors. Wand movement: gentle upwards sweep from the knees. A Class-A Transfigurative Spell. Transfigures dragon statues into dragons. These dragons can emit the purest of flames which can be used in Goblin Finery and potion making. Does not create real life due to Gamp's Law of Elemental Transfiguration.

Dragon - Winged, fire-breathing, extremely dangerous reptiles. Some known breeds are Chinese Fireballs, Swedish Short-Snouts, Common Welsh Greens, Hungarian Horntails, Hebridean Blacks and Norwegian Ridgebacks. They are highly magical: their blood has 12 uses, their dung is an excellent fertiliser, their heartstrings are used in wands, their hide is useful as protective clothing, and parts of their body are used in potion making. 

Dragon Dung - Fertiliser for soil or compost. It breaks down materials quickly because of the strong acids found in the dragon's stomach. It is also scentless, possibly because dragons use odourous gases to produce fire.

Dragon-Hide Gloves - Protect the wearer from injuries such as burning. Useful for Herbology and the care of magical creatures.

Draught of Living Death - An extremely powerful sleeping potion which sends the drinker into a deathlike slumber which can last indefinitely. A dangerous potion and difficult to brew. The Wiggenworld Potion can reverse it's effects.

Drooble's Best Blowing Gum - Brand of chewing gum manufactured by Honeydukes. Are guaranteed to never lose its flavour and allows the purchaser to blow bluebell-coloured bubbles which do not pop for days.

Dried Nettles - See 'Nettle'