In this article, I examine the properties of the partial null subject languages (NSLs) when compared with the consistent and the discourse pro-drop languages and argue that the same basic mechanism underlies pro-drop in partial as well as discourse pro-drop: namely, null NP anaphora, as originally proposed in Tomioka 2003 for discourse pro-drop. The two sets of languages show a correlation between the occurrence of null arguments and the availability of a bare nominal in argument position. I suggest that the null element is a default, minimally specified nominal—the same item that arguably appears as a complement of D in pronouns. It is a proform that minimally consists of the categorizing head n, lacking a root, the meaning of which is ‘entity’ (a property that is trivially true of any individual in the domain). nP introduces a variable that may be bound under Existential Closure, yielding the impersonal interpretation; otherwise, its denotation is type-shifted to an individual (ɩ) under the appropriate conditions. The crosslinguistic differences found in the interpretation of the null subject depend on the resources available in particular languages for application of ɩ type-shifting: the (bare NP) languages that lack such resources only have quasi-argumental and impersonal null subjects (semi pro-drop languages). Finally, I show that the idea that pro reduces to [ nP e ] can also be successfully extended to the consistent NSLs, provided it is assumed that, in this type of NSL, the head bearing agreement morphology bears a D-feature and interpretable ϕ-features.