In plain language
Instead of passing a large file or record between steps, the workflow passes a pointer to it.
Example
An app integration returns a dehydrated file pointer, so the file is only downloaded if a later step needs it.
Related terms
Hydrate · Payload · Object · API
Common misconception
A dehydrated reference is not a copy of the data; if the source changes or is deleted before hydration, the result changes too.
Implementation guidance
Use dehydration for large or expensive data, make references stable and authorized, set expiry expectations, and document which steps hydrate them.