A family-immigration concept defining petitioning, eligibility, and sponsorship requirements for family-based immigration benefits. It governs relationship qualification, filing sequence, allocation of visa availability, and sponsorship obligations where required. It does not confer status without required approvals and issuance or adjustment steps and is limited by eligibility bars and evidence requirements. It determines access to immigrant visas or status adjustment and affects timing through availability and filing rules. The concept is generally stable, though eligibility definitions and processing practices may be updated over time.