In the context of link building or backlink profiles, the terms “tier 1,” “tier 2,” “tier 3,” and “tier 4” are used to categorize the quality and authority of the websites that link to a particular domain. Tier 1 refers to high-quality and authoritative websites that directly link to the target domain, while tier 2 consists of websites that link to tier 1 sites, and so on. Each tier represents a level of distance from the target domain in terms of link authority and relevance.
