Punctuation (5)
'punctuation' is the definition.
(I know that colon is a type of punctuation)
This is the entire clue.
(Other definitions for colon that I've seen before include "Panama port; part of intestine" , "Part of the intestine - punctuation mark" , "Part of body; some punctuation" , "Punctuation mark; gut" , "cash" .)
(Other definitions for mark that I've seen before include "Stay close to one's opponent" , "Former German coin" , "Spot - sign - currency" , "bookmaker?" , "Target; become stained" .)