Webster's Revised Unabridged Dictionary · 1913

Invisible

Invisible , adjective

[French invisible, Latin invisibilis. See In- not, and Visible.]

1.
Incapable of being seen; not perceptible by vision; not visible.
(a)
Not visible due to an inherent property, such as lack of color; as, the invisible air; invisible ink;
(b)
hidden from view; out of sight;
(c)
Not perceptible due to lack of light;
(d)
Too small or too distant to be perceived; as, people on the ground invisible at cruising altitude.
To us invisible, or dimly seen In these thy lowest works. — Milton
2.
Hidden from the public; as, invisible transactions.
3.
imperceptible to the mind; as, differences invisible to most observers.
Collocations (2)
Invisible bird (Zoology) , a small, shy singing bird (Myadestes sibilons), of St. Vincent Islands.
Invisible green , a very dark shade of green, approaching to black, and liable to be mistaken for it.

Invisible , noun

1.
An invisible person or thing; specifically, God, the Supreme Being.
2.
A Rosicrucian; -- so called because avoiding declaration of his craft. [Obsolete]
3.
(Ecclesiastical Hist.) One of those (as in the 16th century) who denied the visibility of the church. — Shipley