Commentary explaining the meaning of the ayahs. One passage often covers several ayahs, so neighbouring ayahs can show the same text.
Indoniesua Al-Mukhtasar in Interpreting the Noble Quran tafsir for Surah Al-Insan — Ayah 18
عَيۡنٗا فِيهَا تُسَمَّىٰ سَلۡسَبِيلٗا ١٨
Mereka meminumnya dari sumber mata air di surga yang bernama Salsabīl.