bowsprit (flagpole)

In the boat form of cyclohexane and related structures there are two ring atoms lying out of the plane of the other four; exocyclic bonds to these two atoms pointing in a direction roughly parallel to that plane are called bowsprit, the other two are called flagpole.
PAC, 1996, 68, 2193 (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2201