Try out switch but use terminal employed by the laboratory
I believe the answer is:
test tube
'the laboratory' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'try out switch but use terminal employed by' is the wordplay.
'try out' becomes 'test' ('test' can be a synonym of 'try out').
'switch' shows that the letters should be reversed in order (I've seen 'switched' mean this).
'terminal' indicates one should take the final letters (terminal refers to the end).
'employed by' says to put letters next to each other.
The final letter of 'use' is 'e'.
'but' in reverse letter order is 'tub'.
'test'+'tub'+'e'='TEST-TUBE'
Can you help me to learn more?
(Other definitions for test tube that I've seen before include "experimental site" , "experimental gear?" , "Lab equipment" , "Thin glass receptacle used in laboratory" , "Lab vessel" .)