Radhetyevam Cha Samsiddha - Brahma Vaivarta Purana (4.17.223)

Radhetyevam Cha Samsiddha - Brahma Vaivarta Purana (4.17.223)

Radhetyevam Cha Samsiddha Rakaro Danavachakah.
Swayam Nirvanadatri Ya Sa Radha Parikirtita.

- Brahma Vaivarta Purana, Section 4 [ShriKrishn Janam Khand], Chapter 17, Verse 223 (4.17.223)

The name 'Radha' is a revered Siddha Mantra (a perfected mantra), where 'Ra' symbolizes the bestower, and she herself is the bestower of enlightenment, known as Radha.