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
Information that could be used to identify a specific individual, such as name, address, phone number, or identification number.
Sources:
NIST SP 800-226
under identifying information
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