A hierarchy is a set of objects all of which are connected by a relation that is asymmetric and transitive in the set.

Different kinds of hierarchies result depending both on the kind of object and the specific relation involved. The following is an open list of hierarchies that have some significance in linguistics. For each hierarchy, the constitutive relation is indicated. x is at a lower hierarchical level than y. In the last column, the kind of x and y is indicated.

Kinds of hierarchies
hierarchyconstitutive relationkind of object
taxonomyx is a yconcept
meronymyx is part of ything
complexity hierarchyy is more complex than xconcepts, things
abstractness hierarchyy is more abstract than xconcepts
preference hierarchyy is preferred to xproperty
teleonomic hierarchyx is a means to purpose yprocesses/operations
implicational hierarchyif x has a certain property, then y has that property(propositions about) things
gradiencey has some property to a higher degree than x(propositions about) things