Among the set books at Hogwarts is one called Magical Draughts and Potions. A 'draught' is a portion of liquid drawn (from a cask, etc.) for drinking. A 'potion' is a mixture of liquids (liquor or medicine). Essentially, draughts and potions are both something to be drunk.
In the Vietnamese version, the name of this book is translated Đề cương phép lạ và độc dược meaning Magical Theses and Potions. Theses? How did a draught turn into a thesis?
The answer lies in the very large number of meanings of the word 'draught'. 'Draught' can mean 'a current of air in a room', 'pulling or traction', 'the depth of water needed to float a ship', 'the drawing of liquor from a cask', 'a single act of drinking or the amount drunk in a single act of drinking', and 'the drawing in of a fish net'. Draughts is a board game known in America as 'checkers'.
In addition, the word 'draft', which is essentially the same word as 'draught', means a 'preliminary version of a speech or document', 'a written order for payment of money by a bank', 'the drawing of money', 'a detachment from a larger group', 'the selection of a detachment from a larger group', or 'conscription'. To make matters worse, in American English the spelling 'draught' has dropped out of use; these words are all spelt 'draft'.
Pity the poor Vietnamese translator who had to wade through all these meanings to find the right translation for 'draft', especially if she was translating from the American version! No wonder she mistakenly chose đề cương, which means 'preliminary version of a document'. Yes, the 'thesis' that's referred to in the Vietnamese translation is actually 'a written draft'. The mysterious 'thesis' results from a simple misunderstanding of 'draft'.