What brevity term indicates that an object has been acquired and is being tracked with an onboard sensor?

The brevity term that indicates an object has been acquired and is being tracked with an onboard sensor is "Captured." This term is specifically used in military communication to convey that a target is not only detected but is actively being monitored, which is critical for effective targeting and engagement. When a target is described as "captured," it implies that the necessary systems are engaged and that all requisite data is being collected to facilitate decision-making regarding the next steps, such as targeting or operational maneuvers.

The other terms do not convey the same level of detail or operational context as "captured." For instance, "Ice" might refer to a state of non-movement or inactive status, "Deadeye" typically indicates a specific targeting accuracy or focus on a target, and "Spot" can signify that a target has been identified but does not confirm ongoing tracking with sensors. Each of these carries different operational implications that do not align with the defined purpose of having an active sensor monitoring a target.