Tesseseya has two main classes of nouns: rational and non-rational nouns. Rational nouns include people, deities, and spirits and a few other nouns considered to be somehow rational, such as the sun, moons, and stars. Everything else belongs to the non-rational class. Rational nouns have singular and plural forms, take the object marker =va, have a smaller range of possible classifiers than non-rational nouns, and use the pronominal clitics ma= for singular and nadi= for plural.
Rational nouns distinguish between singular and plural. The plural form of a given rational noun is not always predictable, but derives from a suffix -na. For example:
| edi | a deity or spirit | edena | deities, spirits |
| gene | an elder | genna | elders |
| kidi | a person | kinna | people |
| kiyumu | a man, male person | kiyumona | men |
| luvu | a star | lunna | stars |
Singular forms are used with the singular, dual, negative, collective, and whole determiners. Plurals are used with paucal, plural, greater plural, and sufficient number determiners.
Rational nouns can be derived from other words using the suffix -(y)ele, plural -(y)enna. For example from the modifier niki 'nearby', one can derive the noun nikiyele 'neighbor', plural nikiyenna 'neighbors'.
A subclass of rational nouns are kinship terms. These distinguish who's kin one is referencing. For example, there is no general word for ‘mother’, instead there is lemada 'my mother', limmada 'our mother', ŋimada 'your (sg) mother', ŋimmada 'your (pl) mother', mamada 'his/her mother', and nammada 'their mother', as well as corresponding plural forms suffixed with -na. These likely arose from a combination of the pronominal clitics plus a base form mada, and have become fused over time and are no longer separable.