AEP- Profile Snapshot

In Adobe Experience Platform, a profile snapshot is a system-generated dataset that provides a daily view of your organization's unified profiles, essentially a "snapshot" of your profile data at a specific point in time.

For better or in-depth analysis you can definitely go through with the following Product Document: https://experienceleague.adobe.com/en/docs/experience-platform/dashboards/query#profile-attribute-datasets

And another Community Post related to the same will offer you the better understanding: https://experienceleaguecommunities.adobe.com/t5/real-time-customer-data-platform/profile-snapshot-and-segment-qualification-troubleshooting/ba-p/698998

Hope this will help you for your better learning, in case the answer does not helpful feel free to respond back.