I know "-oid" means "in the form of", but what does the "ol-" in oloid mean?

You may need to be more specific by listing the word you are specifically interested in learning about. Oloid is not a word or root. I am not aware of -ol- by itself having a particular meaning but there are others like "sol" which is sun or alone. Perhaps one of our literary experts will have a better answer to your question and I can withdraw mine.

I meant what is an oloid in the form of, that's the meaning I was asking about.

"Oloid" is the short form of "polysomatoloid". It was discovered in 1929 by German sculptor, technician and mathematician Paul Schatz. The story goes that Schatz named it "polysomatoloid" but as he thought no one could pronounce it, he shortened it - half jokingly - to "oloid".

https://mathcurve.com/surfaces.gb/orthobicycle/orthobicycle.shtml

Another possibility: use of the Greek word "olos" all.

https://mathcurve.com/surfaces.gb/orthobicycle/orthobicycle.shtml

A short sentence that suggests that 'ol' could derive from the Greek word for 'all'.

The theory about Greek "olos" as a root is not really convincing.

1. The Greek word does not mean - as the source suggests - "all" but rather "whole, entire, perfect, complete or absolute". None of these words has a conclusive semantic connection to the object.

2. Greek "olos" generally leads to the English prefix "holo-" as in "hologram", "holistic" and many others.