Because I'm a geek--a little more on this!

Fiber refers to the origin of the textile itself--did it come from a plant, animal, petroleum product? Which one? https://twitter.com/RowennaM/status/1336380925270237190

Natural fibers come from plants and animals.

Synthetic fibers come from petroleum (mostly--rayon comes from wood pulp but is still considered synthetic as it's been reconstituted sorta).

Your most common plant fiber textiles are cotton and linen. You also have ramie (from the nettle family), hemp, bamboo, and more.

For animal fibers, your most common are wool (from sheep or goats) and silk (from silkworms). You also have camelid fibers (camel, llama, alpaca).

So that's just where the fiber CAME from. The weight and weave--what fabric the fiber turns into--is something completely different.

Just about any of these fibers can be woven into a heavy or light or mid-weight fabric.

Plus, just about any can be woven into a sheer or opaque weave (which is about the weight, but also how much space gets left between threads). PLUS the weave patterns vary.

So the most common weaves:

Tabby or taffeta is a plain weave. Like, the over-under pattern that you really don't even think about, your basic cotton broadcloth, your wool coating fabric.

And yes, taffeta silk. (FUN FACT that tabby weave allowed for "changeable" or iridescent silks well before modern dyeing methods--the warp and weft are two different colors producing a super lovely effect.)

Satin is another weave. It "floats" more threads in the weave to increase the fluidity of the drape. Satin is often made of silk, but satin does not equal silk. It can be made from synthetics, cotton, even wool. (Wool satin is sooo cool.)

You also have twill weaves, gauze weaves, and specialty weaves resulting in patterns like Jacquard and dobby (no, not the elf). THE THINGS I COULD SAY ABOUT JACQUARD but I will refrain.

Cool diagrams of some weaves here: https://www.heddels.com/2017/12/7-weave-patterns-to-know-twill-basketweave-satin-and-more/

The really amazing thing about textiles is that through a combination of fiber and weave you can produce a dizzying variety of fabric. For example, though we think of wool as "heavy coat fabric" you can create lightweight wool crepe that would be comfortable in 80 degrees.

Though we think of silk as a satiny, shiny luxe fabric, it can be woven heavy and slubby and into something with the tensile strength of Godzila and exceptionally utilitarian.

We think of cotton as predominantly "that boring quilting fabric" but OH some of the cotton sheers I've seen in my day. SWOOON.

(And this isn't even getting into what you can do when you combine fibers. I'll shut up before I wax poetic on camblet, which is silk and wool combined and has a hand and drape like heaven.)