The Clove Hitch is one of the essential knots and is made of two half-hitches secured around an object.
A “hitch” is used for exactly what it sounds like…hitching a rope to something. In other words it is a securing knot. However the Clove hitch is not particulary strong in that role because it can slip, which strangely enough is what makes it useful. The ability to adjust the Clove Hitch without untying it makes it a useful knot for constructing belay stations and starting lashings.