Definition of "visible"

It cannot be denied it [the chameleon] is (if not the moſt of any) a very abſtemious animall, and ſuch as by reaſon of its frigidity, paucity of bloud, and latitancy in the winter (about which time the obſervations are often made) will long ſubſist without a viſible ſuſtentation.

1650, Thomas Browne, “Of the Cameleon”, in Pseudodoxia Epidemica: […], 2nd edition, London: […] A[braham] Miller, for Edw[ard] Dod and Nath[aniel] Ekins, […], 3rd book, page 133

Although the Celebrity was almost impervious to sarcasm, he was now beginning to exhibit visible signs of uneasiness, the consciousness dawning upon him that his eccentricity was not receiving the ovation it merited.

1897 December (indicated as 1898), Winston Churchill, chapter V, in The Celebrity: An Episode, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., Ltd.

Earless ghost swift moths become “invisible” to echolocating bats by forming mating clusters close […] above vegetation and effectively blending into the clutter of echoes that the bat receives from the leaves and stems around them. Many insects probably use this strategy, which is a close analogy to crypsis in the visible world—camouflage and other methods for blending into one’s visual background.

2013 May-June, William E. Conner, “An Acoustic Arms Race”, in American Scientist, volume 101, number 3, pages 206–7