Half hitch
A simple hitch in which the working end passes around an object and over and under its own standing part; insecure alone but a building block for many knots.
A half hitch is made when the working end of a rope goes around something and then passes over and under its own standing part (Wikipedia, citing The Ashley Book of Knots; Rope365). On its own it is generally insecure, but it is a building block for many other knots: two half hitches, the lark’s head (two half hitches made in opposite directions) and French whipping are all built from it. In rope bondage, Shibari Study describes the half hitch as a figure-4 shape formed around the rope itself or around another rope, weak by itself but useful when several are stacked or when it forms part of a friction.