Buddha nature refers to the stateless state of nirvana, and possesses other names as the eighth vijnana, Tathagatagarbha, Buddha, enlightened, true-suchness, no-mind mind, true mind, Alayavijnana, etc.
In terms of Buddhism, Buddha nature does not belong to any of the worldly sense-objects or discernment, does not possess any of the mundane phenomena. Its different functions and characteristics are beyond the three realms, which are extensively explained in the Lankavatara sutras. It coexists with the five aggregates (skandhas), without any form or appearance. The five aggregates will eventually disintegrate when an individual passes away, but not the Buddha nature.
The Buddha nature is not created; it exists independently, so it will never cease to exist. As you can see, it is timeless.
If an individual practices the correct Buddha’s teachings in accordance with the sutras and follows the instructions from a knowledgeable mentor, eventually his ceaseless Buddha nature will manifest to its fullest magnificent functional distinctions to attain the ultimate Buddhahood.
Let me use an analogy to explain this: A diamond mine is the Buddha nature, after the whole procedures of polishing, a finished product is Buddhahood.
For your reference, Buddhist terminology cannot be interpreted by our own interpretations or speculations, otherwise it is not called Buddhism. Most importantly, practitioners will not benefit anything from worldly conceptual elaborations.