Sensor Observation Service
The Sensor Observation Service (SOS) is a web service to query real-time sensor data and sensor data time series and is part of the Sensor Web. The offered sensor data consists of data directly from the sensors, which are encoded in the Sensor Model Language (SensorML), and the measured values in the Observations and Measurements (O & M) encoding format.
Source: Wikipedia — Sensor Observation Service (CC BY-SA 4.0)