label hierarchy, display

in the database of labels, keep relationships e.g. "isa", (1:many , like traits or multiply inheritance),
display these in the label list, e.g.
if you label some traffic with "car", "van", "hatchback car", "sedan", the list would show:-

vehicle:
truck:
articulated lorry
van
bus:
bus
school bus
double decker bus
car:
car
hatchback car
sedan
pickup truck
sports car
taxi
minibus

more specific labels like 'hatchback car' would still show up as 'car' labels. Allow being as specific as possible with the labelling, whilst still providing broadly useful data.