Setback with town's first underground glass cylinder (4,4)
I believe the answer is:
test tube
'glass cylinder' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'setback with town's first underground' is the wordplay.
'setback' becomes 'tes' (I've seen this in other clues).
'with' means one lot of letters go next to another.
'town's first' becomes 't' (1st letter of 'town').
'underground' becomes 'tube' (the London Underground is nicknamed the Tube).
'tes'+'t'+'tube'='TEST-TUBE'
Can you help me to learn more?
(Other definitions for test tube that I've seen before include "Cylindrical glass in a laboratory" , "glass vessel" , "Glass container in the laboratory" , "'Laboratory glass cylinder (4,4)'" , "Thin glass receptacle used in laboratory" .)