The most common and most likely answer to this crossword clue is the 8 letter word ARTERIES
I've seen this crossword clue in The Daily Telegraph
A
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More clues leading to the result ARTERIES
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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 ARTERIES mean?
ARTERIES noun- An efferent blood vessel from the heart, conveying blood away from the heart regardless of oxygenation status; see pulmonary artery.
- A major transit corridor.