A number without context is useless. “23.4” means something only once you know it came from sensor 17, is in degrees Celsius, was measured in cold room B and was produced by a firmware version with a known calibration offset. Metadata carries that context, usually kept in the device registry or a model such as a digital twin rather than repeated in every payload.
Metadata quality decides whether historical data can be trusted. If a device is moved to another room and nobody updates the record, every later analysis is wrong. Treat metadata changes as events worth logging, version schemas so old files can still be decoded, and make the fields part of data governance.
Part of the IoT Glossary. Spotted an error or a missing term? Tell us.