Ultimate tribute about astronaut's fourth circuit (5)
I believe the answer is:
orbit
'circuit' is the definition.
(synonyms)
'ultimate tribute about astronaut's fourth' is the wordplay.
'ultimate tribute' becomes 'obit' (I've seen this before. I am not sure about the 'ultimate' bit.).
'about' means one lot of letters goes inside another.
'astronaut's fourth' becomes 'r' (tth letter of 'astronaut').
'obit' placed around 'r' is 'ORBIT'.
Can you help me to learn more?
(Other definitions for orbit that I've seen before include "Satellite's path" , "Field of influence" , "Particular environment" , "Circling path" , "Circumnavigate" .)