Gender systems are endlessly fascinating, from those where meaning determines gender (Tamil), those where it is dominant but leaves intriguing loopholes (Mian) to those where form has an important role (Russian). Now it is time to integrate these systems into a fuller typology of nominal classification, taking in classifier systems as well as gender. Rethinking in this way leads us to take apart characteristics usually lumped together as defining gender, and those defining traditional classifiers. We then see that these characteristics combine in many ways. A canonical perspective proves helpful: we define the notion of canonical gender, and use this idealization as a baseline from which to calibrate the rich variety we find. It is then possible to approach the origin and nature of gender. Here Oceanic languages can provide a unique insight. Typically, a noun can occur with different possessive classifiers, depending on how the possessed item is used by the possessor: ‘my water (to drink)’ vs ‘my water (for something else)’. But in marked contrast, languages like North Ambrym (Vanuatu) typically have particular nouns occurring with one given classifier: water is just drinkable (Franjieh 2016). North Ambrym’s innovative system resembles a gender system: a noun takes a particular classifier regardless. We want to establish empirically whether gender systems can indeed emerge from possessive classifiers in this way. We must also uncover how and why languages would relinquish a useful, meaningful classificatory system, and move to a more rigid gender system. To this end we are running novel experiments to compare possessive classifier systems in six Oceanic languages of Vanuatu and New Caledonia, each with a different inventory size of classifiers — from two to twenty-three. Combining typology with psycholinguistics in this way promises to shed new light on how systems of nominal classification develop and function. The Oceanic data suggest that, in this instance, we find an interesting parallelism: diachronic change is running in the direction of canonicity.