«مَنْ لَقِيَ النَّبِيَّ ﷺ مُؤْمِنًا بِهِ، وَمَاتَ عَلَى الْإِسْلَامِ»
A Companion is someone who met the Prophet ﷺ while believing in him and who died upon Islam.
There are three essential elements: meeting the Prophet, belief in him at that meeting, and remaining or returning to Islam at death. If a relevant condition is missing, technical Companion status cannot simply be assumed.
The definition does not require years of association, accompanying journeys, sitting in many assemblies, or transmitting a hadith. Its purpose is to identify the generation that attained the distinction of meeting the Prophet in faith, not to measure how many reports an individual narrated.