Soul as a (fundamental) substance- The Skandha (aggregate) of innumerable Pradeśas (the indivisible units of the substance) each of which is possessed of Caitanya (sentience).
trikālānugāmyiipasarjanikṛtakaṣāyādiparyāyaṃ tadrūpa ātmā dravyātmā sarvesāṃ jīvānāṃ......dravyātmatvaṃ jīvatvamityarthaḥ.
(Bhaga 12.200, 201 Vṛ)
See - Jīva.