opacous

English

Etymology

From Latin opacus (“shaded, shady, dark”) +‎ -ous.

Adjective

opacous (not comparable)

1. (obsolete, chiefly poetic) Not shining or illuminated; dark. [17th–20th c.]
   • 1667, John Milton, “(please specify the book number)”, in Paradise Lost. […], London: […] [Samuel Simmons], […], →OCLC; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873, →OCLC:

     The firm opacous Globe / Of this round World, whose first convex divides / The luminous inferior Orbs.

2. (obsolete) Not allowing the passage of light; opaque. [17th–19th c.]
   • 1659 December 30 (date written), Robert Boyle, “[Experiment 37]”, in New Experiments Physico-Mechanicall, Touching the Spring of the Air, and Its Effects, (Made, for the Most Part, in a New Pneumatical Engine) […], Oxford, Oxfordshire: […] H[enry] Hall, printer to the University, for Tho[mas] Robinson, published 1660, →OCLC, page 309:

     And vve particularly remember, that, being at ſome diſtance from London one Night, that the People, upon a very vvell-come Occaſion, teſtified their Joy by numerous Bon-fires; though, by reaſon of the Interpoſition of the Houſes, vve could not ſee the Fires themſelves, yet vve could plainly ſee the Air all enlighten'd over and near the City; vvhich argu'd, that the lucid Beams ſhot upvvards from the Fires, met in the Air with the Corpuſcles opacous enough to reflect them to our Eyes.

   • 1665, R[obert] Hooke, chapter X, in Micrographia: Or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses. With Observations and Inquiries thereupon, London: Printed by Jo[hn] Martyn, and Ja[mes] Allestry, printers to the Royal Society, […], →OCLC:

     [I]f you take ammel that is almost opacous, and grind it very well on a Porphyry, or Serpentine, the small particles will by reason of their flaws, appear perfectly opacous […]

   • 1681, Nehemiah Grew, Musæum Regalis Societatis. Or A Catalogue & Description of the Natural and Artificial Rarities Belonging to the Royal Society and Preserved at Gresham Colledge. […], London: […] W. Rawlins, for the author, →OCLC:

     The upper wings are opacous; at their hinder ends, where they lap over, transparent, like the wing of a fly.