I am interested in how a structure of the following representation would be called or if there even is an established definition of such a thing.
The structure is similar to a graph. The representation shown here has the following meaning:
 There are nodes
A
,B
andC
.  There are edges
x
andy
.  Node
A
has an edgex
to nodeB
.  Node
C
has an edgey
to edgex
.
The first three sentences are typical descriptions for a graph. The last one does not fit into the definition of a graph. Here is a representation:
(A)x>(B)
^


y


(C)
This example could too be modeled using multiple graphs, lists or other structures, but I hope to find something more 'native'.