The process of linking multiple device identifiers (mobile, desktop, CTV) to a single individual or household, enabling consistent audience measurement across touchpoints.
A person might browse on their phone at lunch, research on a laptop that evening, and walk into the store on the weekend cross-device matching is what links those three touchpoints back to one person (or household) so a marketer isn’t double-counting reach or missing the connection between an ad exposure and an eventual visit.
Further reading: Evaluating identity resolution partners · Identity layer
