A Subsistence

1. Real being; existence.
2. The act of maintaining oneself at a minimum level.
3. Inherency.
4. Something (food, water, money, etc.) that is required to stay alive.
5. (theology) Embodiment or personification or hypostasis of an underlying principle or quality.

(real being): existence

(something required to stay alive): sustenance

(theology): hypostasis