Pass over stretch of canal (5)
I believe the answer is:
colon
'stretch of canal' is the definition.
The definition and answer can be both body parts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'pass over' is the wordplay.
'pass' becomes 'col' (col is a kind of pass**).
'over' becomes 'on' (I've seen this in other clues).
'col'+'on'='COLON'
Can you help me to learn more?
(Other definitions for colon that I've seen before include "Panama port; part of intestine" , "cut short dependency?" , "that may cut sentence" , "Punctuation mark; gut" , "Costa Rican currency" .)