Most of us are familiar with the wool that our parents or grand-parents knitted with. Let’s use that wool as a generic example.
That wool is a YARN. It is a spun thread.
It is made of individual fibres that have been spun together to make the yarn. Fibres are threads or filaments or perhaps even animal hair.
The yarn can be woven into weaves/patterns. Usually a weave has many long thread running running as a warp through a roll of fabric. That weave typically also has another yarn running at ninety degrees from left-to-right called the weft.
Fairly simple. On the whole.
Knitting is not really weaving. Lots of kinds of weaves are used in knitting but knitting includes other methods as well as weaving. I’ll stop there !