One of the schematic categories in the configurational system. Plexity relates to whether a quantity of time or space consists of one (uniplex) or more than one (multiplex) equivalent elements. When related to space (or matter), this is the basis of the grammatical category number. For instance, the singular count noun slipper represents uniplex structure, while the plural count noun slippers represents multiplex structure. Mass nouns like champagne also have multiplex structure.

When related to the domain of time (or action), plexity forms part of the basis for the distinction in lexical aspect between semelfactive (one instance) versus iterative (repeated instances). This is illustrated below:

1. Max coughed (semelfactive)
2. Max coughed for ten minutes (iterative) The verb cough encodes a punctual event, and thus encodes semelfactive aspect which has uniplex structure.

Iterative lexical aspect has multiplex structure.