A V formation is a V-shaped group flight pattern used by birds. The shape can reduce effort by letting individuals benefit from airflow created by others, but the key point for analysis is that a visible pattern can hide the real mechanism underneath it.
In cyber security, the term is useful as an analogy for coordinated behavior: traffic, alerts, or host activity may appear orderly while a hidden control path or shared dependency drives it. Defenders look for the mechanism behind the pattern by correlating logs, mapping lateral movement, and tracing command-and-control behavior. Attackers also rely on this idea, using distributed actions that seem separate but form a deliberate shape when viewed together. The lesson is to inspect the wake, not just the outline.