Answer provided by laboratory vessel (6)
I believe the answer is:
retort
I believe this is a double definition.
'answer' is the first definition.
(I know that retort is a type of answer)
'laboratory vessel' is the second definition.
(I've seen this in another clue)
'provided by' acts as a link.
(Other definitions for retort that I've seen before include "Witty reply" , "A sharp reply or vessel used in distilling" , "Answering remark" , "Quick and clever or angry reply" , "Riposte, reply" .)