A rounded, underwater hill with a prominence of less than 1,000 metres, which does not breach the water's surface.
A small mound or rounded hill.
A knell.
To ring (a bell) mournfully; to knell.
To sound (something) like a bell; to knell.
To call (someone, to church) by sounding or making a knell (as a bell, a trumpet, etc).
To arrange related objects in parallel or at 90 degree angles.