To tie a line around a timber or post so that it will hold temporarily but can be readily undone, this is defined as:

The term for tying a line around a timber or post to hold it temporarily, yet allowing it to be easily undone, is defined as a hitch. A hitch is specifically designed for this purpose; it creates a secure yet adjustable connection that can be released easily.

Hitches are frequently used in various applications, such as securing loads, setting up tents, or any scenario where a connection is needed that doesn't require the permanence of other types of knots. They can be quickly tied and untied, providing flexibility for temporary setups.

In contrast, the other terms refer to different types of uses; a knot usually involves tying two ends of rope together securely, a loop typically describes the form of the line without necessarily anchoring it, and a bend refers to tying two ropes together. While these may also be useful in different contexts, they do not embody the specific characteristics of being easily undone while providing temporary security as a hitch does.