Lark's head
A hitch of two half hitches made in opposite directions, also called the cow or girth hitch; in rope bondage often used to attach or join ropes.
The lark’s head is the knot that knot books call the cow hitch; it also goes by girth hitch, ring hitch and many other names. It is formed from two single hitches made in opposite directions, whereas a clove hitch has both in the same direction, and it can be tied with an end or with a bight. Clifford Ashley traced the name lark’s head to an 1866 English knot book believed to be adapted from French, in which the knot is the tête d’alouette. In rope bondage it is used to attach a rope to an object and to join or extend ropes (Shibari Study; Anatomie Studio). Its Japanese name, hibari musubi (雲雀結び), means skylark knot (Andrea Ropes; Jisho).