The most common and most likely answer to this crossword clue is the 4 plus 4 letter word TEST TUBE
I've seen this crossword clue in The Guardian
T
E
S
T
T
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More clues leading to the result TEST TUBE
- Try out underground piece of laboratory apparatus
- Examine underground laboratory item
- Where reactions happen, conversely, in wine-butts etc
- Experimental equipment for examination underground
- Cricket match underground as part of an experiment
- River transport laboratory item
- Technical equipment to probe underground
- Underground river first experimental site
- Check underground for baby?
- Experimental equipment fixed up underground — about time!
Buddy explains!
The straight part
We know that "lab equipment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lab equipment = test tube.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.