Rising bit of smoke's permeating support for lab kit (4,4)
I believe the answer is:
test tube
'lab kit' is the 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?
'rising bit of smoke's permeating support' is the wordplay.
'rising' says the letters should be written backwards (letters written upwards in a down clue).
'bit of smoke's' becomes 'butt's' (remains of a cigarette or 'smoke').
'permeating' means one lot of letters goes inside another (some letters permeate or go through others).
'support' becomes 'tee' (tee is a kind of support).
'butts' reversed gives 'sttub'.
'sttub' going within 'tee' is 'TEST-TUBE'.
'for' is the link.
Can you help me to learn more?
(Other definitions for test tube that I've seen before include "Item of laboratory equipment" , "Experimental glassware" , "part of an experiment" , "Laboratory glassware" , "Ling glass cylinder used in laboratories" .)