κάβος
Two meanings. 1) a cape or headland and 2) the thick mooring rope used to secure a boat
Παίρνω κάβο = to begin to understand, the penny drops
I saw it used with the verb ξεπερνώ as in ξεπέρασε η κυβέρνηση τον κάβο… meaning the government had got round one problem.
Not to be confused with κάβα, which is a wine cellar or a place for storing alcohol. Now it is most commonly used to describe an upmarket outlet for fine wines, craft beers and more expensive spirits. Some κάβες are very impressive but be prepared to part with some serious money.