str.istitle(): Return True if the string is a titlecased string and there is at least one character, for example uppercase characters may only follow uncased characters and lowercase characters only cased ones. Return False otherwise.

I saw this description from the doc. But what does "cased" andd "uncased" mean? I looked it up on a dictionary, and the latter only says: "cased in something: completely covered with a particular material".

I think "cased" may be "capitalized", but, if so, the usage of the former is not endorsed by dictionaries so that I think this word is confusing or informal. so does "uncased".