Medicine uses "occult" for hidden too, e.g. occult blood in Uranus may be a sign of polyps or cancer. As distinct from non-occult blood, which is probably just

Medicine uses "occult" for hidden too, e.g. occult blood in Uranus may be a sign of polyps or cancer. As distinct from non-occult blood, which is probably just from asteroids. https://en.wikipedia.org/wiki/Fecal_occult_blood https://en.wikipedia.org/wiki/Fecal_occult_blood