• Companion (صحابی): someone who met the Prophet ﷺ as a believer and died upon faith.
• Successor (تابعی): someone who was not a Companion but met a Companion as a believer. The plural is tābiʿīn (تابعین).
In this division, the start of the sanad refers to the generation of Successors receiving the Hadith from the Companion.