From Hindupedia, the Hindu Encyclopedia
By M. A. Alwar
Indrasurasaḥ is a masculine form
It is derived from 'indraḥ indravṛkṣa iva surasaḥ supathyarasaḥ which means whose juice is wholesome like the indravṛkṣa.
As per Amara
It is known as Sinduvāra tree (Vitex negundo) according to Amara.
As per Hindi
It is known as nisindā in Hindi language.
Details of Indrasurasaḥ can be seen under the words Sinduvāra and Nirguṇḍī.
- Shabdakalpadrumah by Raja Radhakantdev, Varadaprasada Vasu, Haricarana Vasu