Information that can be used to distinguish or trace an individual's identity, either alone or when combined with other information that is linked or linkable to a specific individual.
Sources:
NIST SP 800-188
under identifying information
from
OMB M-17-12
The set of an asset's attributes that may be useful for identifying that asset, including discoverable information about the asset and identifiers assigned to the asset.
Sources:
NISTIR 7693