[…] so long as the independent word, in its individual shape and meaning, is plainly recognized in the combination, so long does this remain a compound rather than a form […].
- Whitney (1875), a pag.124

How ready the language-users are to forget the source of the compound, to lose the separate impression of its constituent words, to use it as a unitary sign for the conception to which it is attached, and then to disguise and integrate it by phonetic change, has been […] pointed out […].
- Whitney (1875), a pag.122

So long as the word which enters into combination with another retains its own shape unaltered, the product is a compound only, but when, by phonetic change, its origin and identity with still subsisting independent word are hidden, the compound becomes rather a derivative.
- Whitney (1875), a pag.52

Such a word [compound] is logically an abbreviated descriptive phrase, with the signs of relation, the ordinary inflections or connectives, omitted; the two main ideas are put side by side, and the mind left to infer their relation to one another from the known circumstances of the case. It is so far an abnegation, for the sake of brevity and convenience, of the advantages of a language which has formative elements and form-words. The undefined relation may be of every variety […] Such a word [compound] again is formally characterized by a unity of accent; this is the chief outer sign of combination, binding the word together- although it is not enough of itself to make a compound […].
- Whitney (1875), a pag.121