Is there a standard name for this tree structure?

[Duncan Booth]

Steven D'Aprano <steve at REMOVE-THIS-cybersource.com.au> wrote:

> I have a hierarchical structure something like a directory tree or a 
> nested tree structure:
> 
> Mammal
> +-- Ape
>:   +-- Chimpanzee
>:   +-- Gorilla
>:   +-- Human
> +-- Carnivore
>:   +-- Cat
>:       +-- Tiger
> Reptile
> +-- Lizard
> +-- Snake
>     +-- Cobra
>     +-- Python
> 
...snip...
> Is there a particular name for this structure? I've been calling it a 
> dict-based flattened tree, but I can't shake the feeling that there is 
> another name for it...
> 
Do you have any carniverous apes? If so it's a directed acyclic graph.