Degree readings of size adjectives, as in big stamp-collector, cannot be explained away as merely the consequence of some extragrammatical phenomenon. Rather, this paper proposes that they actually reflect the grammatical architecture of nominal gradability. Such readings are available only for size adjectives in attributive positions, and systematically only for adjectives that predicate bigness. These restrictions can be understood as part of a broader picture of gradable NPs in which adnominal degree morphemes—often overt—play a key role, analogous to their role (...) in the extended AP. Size adjectives acquire degree readings through a degree morpheme similar to the one that licenses AP-modifying measure phrases. Its syntax gives rise to positional restrictions on the availability of these readings, and the semantics of degree measurement interacts with the scale structure of size adjectives to give rise to restrictions on the adjective itself. (shrink)