difference between twisted and turned

Question

  "Three up... two across he muttered. "Right, stand back, Harry."
   He tapped the wall three times with the point of his umbrella.
   The brick he had touched quivered –– it wriggled –– in the middle, a small hole appeared –– it grew wider and wider –– a second later they were facing an archway large enough even for Hagrid, an archway onto a cobbled street that twisted and turned out of sight.
   "Welcome," said Hagrid, "to Diagon Alley."
(Harry Potter and the Sorcerer's Stone)

From the context, ‘twist’ seems to mean ‘bend slightly not to out of sight’; ‘turn’ ‘curve enough to be out of sight’. Is it what the two words really mean?

Answer 1

Twist and turn is a common collocation. Semantically, it's a single unit meaning "a number of intricate twists and turns". It can appear with both words in noun form:

• Twists and turns
• Every twist and turn

Or in various verb forms, meaning "twisting and turning many times, in intricate fashion":

• Twist and turn
• Twists and turns
• Twisted and turned
• Twisting and turning

And so on. I suggest you not try to analyze the meaning of the two words separately. Instead, analyze the pair like this:

... a cobbled street that [twisted and turned] out of sight.

In other words, as though it's a single verb.