قَالَ مُصَنِّفُ هَذَا الْكِتَابِ رَحِمَهُ اللَّهُ سُمِّيَتِ الدِّيَةُ عَقْلًا لِأَنَّ الدِّيَاتِ كَانَتْ إِبِلًا تُعْقَلُ بِفِنَاءِ وَلِيِّ الْمَقْتُولِ.
The compiler of this book (may Allah سبحانه وتعالى have mercy on him) explained that Diyyah was called 'aql because in the past, blood money was paid in camels that were tied (tu'qal) in the courtyard of the guardian of the slain person.