Linguists have used different sets of criteria to determine the "head" of a given construction. These criteria have sometimes led scholars to single out rather different constituents of NP constructions as the "head" in various languages. Maa (Eastern Nilotic) nominal lexeme stems (N's) fall into at least 5 different groups according to their interaction with head properties. We explore this by looking at Determiner-N combinations relative to what determines the number and gender of the whole NP (NP-internal properties) and what allows the NP to distribute in syntax as a subject (an NP-external issue). We show that these criteria do not always single out the same structural element in the Maa NP construction as the "head". The determiner of number marking in the NP construction is the lexical (usually nominal) stem; all other number marking within the NP is a manifestation of agreement. As for gender, some lexemes have lexicalized gender while others do not. In the first type, the lexeme determines gender assignment of the whole NP. In the second, gender is mostly registered only in the determiner, and the assignment of gender for the entire construction depends on determiner choice. As for external distribution, the primary lexical slot in the NP construction can be filled by nouns, adjectives, adverbs, relative clauses and genitive nouns. In themselves, these have otherwise widely different distributions, so the distribution of the entire construction, at least in core argument slots, is determined by the determiner slot.