[...] "basic convention denoting the semantic mechanism of nominal compounds": "(N1: N2)N, where N1 and N2 represent the semantic content of the constituent nouns of a compound, and the subscript N designates the grammatical category of the compound... Each mechanism which generates a class of compounds consists of this convention together with a condition specifying the semantic relationship between the constituents of the compounds. Such a condition functions as a constraint on the nouns which may be concatenated to become compounds".
- Downing (2004), a pag.175