Take three L-structures: $\cal{M}_0 \subset\cal{M}_1 \subset\cal{M}_2$. If $\cal{M}_0 \prec \cal{M}_2$ and $\cal{M}_1 \prec \cal{M}_2$, then we have $\cal{M}_0 \prec \cal{M}_1$.
Does this property have a name?
Take three L-structures: $\cal{M}_0 \subset\cal{M}_1 \subset\cal{M}_2$. If $\cal{M}_0 \prec \cal{M}_2$ and $\cal{M}_1 \prec \cal{M}_2$, then we have $\cal{M}_0 \prec \cal{M}_1$.
Does this property have a name?
This is one of the axioms of abstract elementary classes, and in that context it is called "coherence".