Whether we take a construction such as 'RpH', or a more inclusive one like 'FB', or the domain of various constructions such as the word, we always do it on the basis of certain features of relation among the morpheme classes (and sequences) involved. We take all instances of the construction or domain in question as being identical in respect to these features. Such features would be stated for the construction as a whole, i.e. for all instances of it.These features will often be the types of classes, sequences, or components involved; their order (including such unusual orders as the staggered 'R' and 'p': 'kataυ' from 'k-t-υ' plus '-a-a-'); stress and intonation; which classes are occasionally free and which are always bound; what is the smallest, largest, or usual number of classes that occur in instances of the construction; etc. A feature of a construction may also be the primacy of one of its classes over the others. For example, 'X' could be considered primary and 'Y' secondary in a construction if 'X' occurred in every instance of the construction while 'Y' appeared only in some instances. Various different constructions, including construction types grouped together in some one domain such as a word, may be similar to each other in some of these features, or in particular aspects of them; for example, certain constructions may all have their primary class first in the construction. A particularly frequent features of constructions, and of all constructions having the same domain, is their relation to contours and junctures […] Thus in the Semitic example above, all word constructions, and only word constructions, had precisely one main stress; and compound word always had a secondary stress on each sub-construction ('FB') before the last.
- Harris (1951), a pag.328

It is possible to investigate the relation of each construction type to longer constructions which enclose it, and to the whole utterance in which it is contained. A step in this direction is taken when we state whether a construction contains free or bound forms; for this means that members of the construction sometimes or never constitute by themselves the whole utterance in which they are contained. Or we can say that almost all English utterances contain at least one of the free classes ('A, N ¹, V ¹, D', etc.) or the bound classes ('Na',several 'T' and 'P', etc.) grouped around each of these. If each of these free classes, and the sequence of bound classes 'S+E', each with or without any of its accompanying bound classes, is not divisible into smaller sections which occur as complete utterances, then each of these constructions satisfies the two conditions for being a minimum utterance of the language.
- Harris (1951), a pag.329

All constructions which enclose more than one-unit-length construction, but no others, may be said to have the next higher (second order) constructional domain. In many languages, this may be the domain of compound words. We may now proceed to those constructions which occasionally enclose constructions of the second-order domain. For simplicity, we might take certain sequences comprising English 'N⁴' as covering a third-order domain, since some of the constructions enclosed in such a sequence may be of the second order: 'that old bookworm'. Note that not every construction enclosed within 'N⁴' is of the second order: 'that' is not, nor is 'old' (although 'old' can be replaced by one which is, as in 'that sour-faced bookworm'). None of the constructions in a particular 'N⁴' ('that old fellow') need be of the second order; but the fact that several of them can be replaced by second-order constructions ('that old bookworm') makes it desirable to consider 'N⁴' even then as being of the third order. [...] As we establish the constructions of some particular order, we define them in each case as possible sequences of constructions of lower orders. Thus, for English, the first-order word construction was defined as containing one member of 'N' or 'V' or 'A', etc., with or without certain accompanying bound classes. The second-order compound word was defined as containing two or more words plus the '— ' ' — contour. The third-order phrase constructions could be very roughly defined in terms of words and compound words: e.g. the noun phrase would usually contain 'T' 'D' 'A' 'N', where each class and each partial sequence of classes can be repeated with a member of '&' before the second occurrence; any 'D', 'A', or 'N' could be a compound word. This procedure may be repeated until we find no larger construction or domain, in any utterance no matter how long, which we can describe as a regular combination of the last previously established domain.
- Harris (1951), a pag.331