Etymology From Middle English opake, from Latin opacus (“shaded, shady, dark”) (of unknown origin), later reinforced from Middle French opaque. Doublet of ubac.
1
Neither reflecting nor emitting light.
We have agreed that heat is energy to begin with. Light is also a form of energy for when absorbed by any opaque substance it turns completely into heat.1968, Isaac Asimov, Photosynthesis, Basic Books, Inc., page 60:
2
Allowing little light to pass through, not translucent or transparent.
3
Figuratively Unclear, unintelligible, hard to get or explain the meaning of.
Computing, Engineering, Mathematics, Natural sciences, Physical sciences, Sciences Describes a type for which higher-level callers have no knowledge of data values or their representations; all operations are carried out by the type's defined abstract operators.
Etymology From Middle English opake, from Latin opacus (“shaded, shady, dark”) (of unknown origin), later reinforced from Middle French opaque. Doublet of ubac.
1
Obsolete, Poetic An area of darkness; a place or region with no light.
Through this opaque of Nature and of Soul, / This double night, transmit one pitying ray, / To lighten, and to cheer.1745, Edward Young, Night-Thoughts, section I:
2
Something which is opaque rather than translucent.
They can be obtained in various thicknesses and in many colors, including beautiful imitations of pearl, mother-of-pearl, veins and mottles, stratifications, roll stratifications, imitation corals, and all colors of translucents, transparents and opaques, grained ivory, shell (plain and corrugated mottle), onyx, wood effects, plaids, checks, stripes, metallic, bronze pearl plain, bronze pearl with fancy blocks, bronze pearl in veins and stripes, and what is called “essence pearl.”1935 March, F. L. Nowosatka, “Making Colorful Modern Rings from Old Toothbrush Handles”, in Raymond J. Brown, editor, Popular Science Monthly, volume 126, number 3, New York, N.Y.: Popular Science Publishing Co., Inc., →ISSN, →OCLC, “The Home Workshop” section, page 97, column 2:
opaque
verb
Etymology From Middle English opake, from Latin opacus (“shaded, shady, dark”) (of unknown origin), later reinforced from Middle French opaque. Doublet of ubac.