Belonging to the ordering of kinds by rank. Of the work of saying what a thing sits under.
From taxonomy, Greek τάξις (taxis, arrangement) + νόμος (nomos, law); belonging to the ordering of kinds by rank, the same ordering taxonomy itself names.
Describes an act of placement rather than a property of the thing placed — saying what something sits under, not what the something is. The ordering does the work here, not the object being ordered.