Which of the following describes a "gateway" in BPMN?

A gateway in Business Process Model and Notation (BPMN) is indeed described as a decision point that routes processes based on conditions. Gateways serve a crucial role in process flow by controlling the divergence and convergence of sequences based on certain criteria or conditions. They can facilitate decisions, parallel processing, and branching within a process, making them essential for modeling complex workflows.

For instance, when a process reaches a gateway, it can evaluate conditions to determine which path to follow next. This allows for a more dynamic and responsive process that can adapt based on varying inputs or states. Different types of gateways, such as exclusive, inclusive, and parallel, help define how the process behaves under different scenarios.

The other options do not accurately capture the function of a gateway. An event that halts process execution represents something different, as it involves pausing or stopping the process rather than guiding its flow. An input to an ongoing process refers to data or information being fed into a process, and a storage area for process data pertains more to databases or repositories rather than the routing function of a gateway. Thus, the definition that a gateway is a decision point aligning with conditions captures its purpose effectively within BPMN.