What is sugar alcohol?

My wife and I have been reading labels on many products, since my diagnosis of type 2 diabetes.
We noticed some labels showing sugar alcohol.
How is that in relation to sugar, as I do not have any ideas.

As a kid, I had to learn a list: “sucrose, fructose, dextrose, sorbitol, mannitol, dulcitol, xyletol, saccharin, hydrogenated starch hydrolsate, high fructose corn syrup.” I think there were a couple of others. I was taught that these were all forms of sweetener. Some were “safe,” some weren’t. All should be approached in moderation. Sugar-free products have these sugar alcohols in them as artificial sweeteners. Most people can ingest them with very little effect on blood sugar, but others are more sensitive. Sucrose is, of course, table sugar. And HFCS is liquid evil. Everything else on the list was essentially fair game in moderation. At least that was my dietitian’s opinion in 1990.

From Wikipedia:

As a group, sugar alcohols are not as sweet as sucrose, and they contain fewer calories than sucrose. Their flavor is like sucrose, and they can be used to mask the unpleasant aftertastes of some high intensity sweeteners. Sugar alcohols are not metabolized by oral bacteria, and so they do not contribute to tooth decay.[citation needed] They do not brown or caramelize when heated.

In addition to their sweetness, some sugar alcohols can produce a noticeable cooling sensation in the mouth when highly concentrated, for instance in sugar-free hard candy or chewing gum. This happens, for example, with the crystalline phase of sorbitol, erythritol, xylitol, mannitol, lactitol and maltitol. The cooling sensation is due to the dissolving of the sugar alcohol being an endothermic (heat-absorbing) reaction, one with a strong heat of solution. [1]

Sugar alcohols are usually incompletely absorbed into the blood stream from the small intestines which generally results in a smaller change in blood glucose than “regular” sugar (sucrose). This property makes them popular sweeteners among diabetics and people on low-carbohydrate diets. However, as for many other incompletely digestible substances (such as dietary fiber), overconsumption of sugar alcohols can lead to bloating, diarrhea and flatulence because they are not absorbed in the small intestine. Some individuals experience such symptoms even in a single-serving quantity. With continued use, most people develop a degree of tolerance to sugar alcohols and no longer experience these symptoms. As an exception, erythritol is actually absorbed in the small intestine and excreted unchanged through urine, so it has no side effects at typical levels of consumption.