What is the meaning of “[*.]” in the Chrome cookie exceptions dialog?

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Screenshot of the add-to-cookie-whitelist pop up (chrome://settings/cookies?search=cookies)

I am always entering the metacharacters (*.) here, what is their meaning? Do i correctly guess that () means zero or one, * means one or more letters from “a” to “z”, and . means the literal “.”?

(some 300+ points owner: would you be so kind to append metacharacter to the tags of this question and then delete this paragraph?)