interlace

Interlace is a general term for decorative shapes resembling cord, or rope, which twist together into knot-like patterns.

Interlace appears across many different cultures and art styles. It has a particular association with Celtic (in the form of celtic knots), Islamic, Roman, and southern European art.

Notes on usage:
Interlace specifically refers to patterns using thin, abstract lines that form "knots".
Patterns consisting of looping spirals are instead called scrollwork.
In Islamic art in particular, a pattern resembling interlace but using plant forms is common. This is arabesque.