Key not offering opening to this source of medicine? (4)
I believe the answer is:
vial
This clue might be a double definition.
'key not' is the first definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'opening to this source of medicine?' is the second definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'offering' is the link.
Can you help me to learn more?
(Other definitions for vial that I've seen before include "Small container for liquid medicine" , "Small medicine bottle" , "Ampoule" , "Small glass container" , "Bottle that contains a drug" .)