The most common and most likely answer to this crossword clue is the 6 letter word MEATUS
I've seen this crossword clue in The Times
M
E
A
T
U
S
More clues leading to the result MEATUS
Buddy explains!
The straight part
We know that "canal" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case canal = meatus.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 MEATUS mean?
MEATUS noun- A tubular opening or passage in the body.