Occult, a.
Etymology: [L. occultus, p.p. of occulere to cover up, hide; ob (see Ob-) + a root prob.akin to E. hell: cf. F. occulte.]
Hidden from the eye or the understanding; inviable; secret; concealed; unknown. It is of an occult kind, and is so insensible in its advances as to escape observation. I. Taylor. Occult line (Geom.), a line drawn as a part of the construction of a figure or problem, but not to appear in the finished plan. -- Occult qualities, those qualities whose effects only were observed, but the nature and relations of whose productive agencies were undetermined; -- so called by the schoolmen. -- Occult sciences, those sciences of the Middle Ages which related to the supposed action or influence of occult qualities, or supernatural powers, as alchemy, magic, necromancy, and astrology.
1 other Webster entry under this spelling
Occult, v. t.
To eclipse; to hide from sight.
Shades of meaning
Fernald has no entry of its own for occult; he lists it under mysterious.
He lists it without comment; the entries above explain its neighbors.