Anaesthetic hitch -- temperature's dropped (5)

I believe the answer is:

ether

I'm a little stuck... Click here to teach me more about this clue!

'anaesthetic' is the definition.
(ether is a kind of anaesthetic)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for ether that I've seen before include "There goes the anaesthetic" , "Imaginary interstellar medium" , "Once widely-used anaesthetic" , "Anaesthetic is, strangely, there" , "Highly flammable liquid once used as an anaesthetic" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.