Phylogenetic refers to something that is related through evolution. It describes a branching pattern or tree-like structure showing the evolutionary relationships among various organisms, species or groups. In phylogeny, it's about tracing back the lineage of descent from one ancestor to another and constructing an evolutionary history of a group of organisms. This can be done through comparing DNA sequences, morphological characteristics, or other traits that are inherited across generations. The resulting diagram is called a phylogenetic tree, which illustrates the common ancestry and divergence of different species over time.