Is Emptiness (Sunyata) a dhamma?

This question arises from a [comment]( https://buddhism.stackexchange.com/questions/49452/is-emptiness-empty-of-dhammas?noredirect=1#comment79502_49452) in a [related post](https://buddhism.stackexchange.com/questions/49452/is-emptiness-empty-of-dhammas) . 1. Is there any mention in the sutras on the Buddha speaking of sunyata as a dhamma? How is sunyata defined? As a phenomena by itself or is it an idea, a concept, a perception, a realization, etc? 2. Is emptiness a characteristic of the Deathless i.e. the Unconditioned as alluded in [this answer](https://buddhism.stackexchange.com/questions/3836/are-there-different-types-of-emptiness-%c5%9a%c5%abnyat%c4%81/3863#3863) ? Thank you.