Adopted work is a User Story that was not known at the beginning of the sprint that came in from an external source as something that needed to be done now.
Most Teams have established a buffer to manage these kinds of issues. However since this is an interruption and potentially disruptive to the Team it increases the risk on delivery of the Sprint Commitment.
We should watch this number carefully and ask, for example, whether this interruption User Story really needed to be dealt with during this Sprint or could have waited to the next. If it happens a lot perhaps the Team should considered shorter Sprints so they are more responsive to the business, for example. In other words, it allows the team to have more planned work.