“Maybe “Spirituality” means one’s “philosophy of life” but if so why call it spirituality?”
– I think it means one’s “philosophy of improving life”.
Why call it spirituality? Good point. People talk about an inner spark, an inner flame, or an inner light, and presumably, spirituality has this attribute associated with it (the pressure to thrive; thriving, surviving, reproducing).
This seems not a million miles away from talk of a “higher self” and “transcendence”. So, perhaps, the “spirit” is defined as this transcendent higher self, in general usage.