Strong’s Greek
G57 — agnostos
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
ἄγνωστος
agnostos — pronounced ag'-noce-tos'
from 1 (as negative particle) and 1110; unknown:--unknown. see GREEK for 1 see GREEK for 1110
1 occurrence in the KJV.
Acts 17:23
For as I passed by, and beheld your devotions, I found an altar with this inscription, TO THE UNKNOWN GOD. Whom therefore ye ignorantly worship, him declare I unto you.