Loose Appositions
As we pointed out above (p. 244), the term "loose" was first used in English grammatical theory with reference to appositions. It would seem that in this field the difference between loose and ordinary parts of the sentence was especially obvious to the authors of grammar books. And indeed, the difference between the type of apposition found in a sentence like As for Uncle Peter, he took it for granted that Scarlett had come to stay (M. MITCHELL} and that in a sentence like 'These two ladies with a third, Afrs Whiting, were the pillars of Atlanta (Idem) is most evident. The ordinary apposition (Uncle) makes a whole with its head.word, it cannot be separated from it either in oral speech (that is, by a pause), or in a written text (that is, by some kind of punctuation mark), whereas a loose apposition (Mrs Whiting) is separated from its head word by these means. Loose appositions can contain various kinds of information about the person or thing denoted by the head word.
Loose Parentheses
Besides those parentheses which consist of one word or of a short phrase and are not separated from the main body of the sentence either in speech or in writing (e. g. perhaps, probably, no doubt, etc.), there are also parentheses consisting of a larger number of words and necessarily separated from the main body of the sentence. Their semantic relation to the sentence is basically the same as with parentheses of the first kind. A few examples will be enough to illustrate the point: They know already, to be sure, and everybody knows of our disgrace. (M. MITCHELL) At all events, I've got as far as that. (FORSTER) Extensive loose parentheses do not appear to be frequent in modern texts.