The most common and most likely answer to this crossword clue is the 9 letter word CORPUSCLE
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Buddy explains!
The straight part
We know that "that may be red or white" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case that may be red or white = corpuscle.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.
What does CORPUSCLE mean?
CORPUSCLE noun- A minute particle; an atom; a molecule.
- A protoplasmic animal cell; especially, such as float free, like blood, lymph, and pus corpuscles; or such as are embedded in an intercellular matrix, like connective tissue and cartilage corpuscles.