Perhaps ultimately, spiritual simply means experiencing wholeness and interconnectedness directly, a seeing that individuality and the totality are interwoven, that nothing is separate or extraneous. If you see in this way, then everything becomes spiritual in its deepest sense. Doing science is spiritual. So is washing the dishes.
Wherever You Go, There You Are: Mindfulness meditation for everyday life (ed. Hachette UK, 2016) - ISBN: 9780349414232