Make new adjustment for sleep, orbiting the earth (5)
I believe the answer is:
reset
'make new adjustment' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'sleep orbiting the earth' is the wordplay.
'sleep' becomes 'rest' (synonyms).
'orbiting' means one lot of letters goes inside another.
'the earth' becomes 'E'.
'rest' placed around 'e' is 'RESET'.
'for' is the link.
Can you help me to learn more?
(Other definitions for reset that I've seen before include "button on electronic device?" , "question that's appeared in exam again" , "Return to original configuration" , "adjusted" , "Put back to original state" .)