crystal clear

• crystal-clear

From Middle English cristal cleer. Emphatic form of clear in visual and metaphorical “understandable” senses. Compare clear as a bell (“very clear (of sound)”).

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crystal clear (comparative more crystal clear or (rare) crystal clearer, superlative most crystal clear or (rare) crystal clearest)

1. (idiomatic, simile) Completely clear (in various senses).

   Synonym: clear as crystal

   1. Without ambiguity or doubt; completely understood.

      Reread through the manual until the instructions are crystal clear in your head.

      • 1943 November – 1944 February (date written; published 1945 August 17), George Orwell [pseudonym; Eric Arthur Blair], Animal Farm […], London: Secker & Warburg, published May 1962, →OCLC:

        Is it not crystal clear, then, comrades, that all the evils of this life of ours spring from the tyranny of human beings?

      • 1997 October 29, Michael Ashcraft, “High tech: Devil made us do it!”, in The Rock Island Argus, 148th year, number 12, Rock Island, Ill., page B1, column 1:

        At a very basic level, technology almost always supplants some level of humanity. Not only does machine power replace manpower, but it distances, if not isolates, us from each other and from reality in the process. / See for yourself. Pick a technology. Any technology. / The crystal clearest example is probably the advance from cannon balls to atom bombs.

      • 2019 September 23, Greta Thunberg, speech at the United Nations:

        For more than 30 years, the science has been crystal clear. How dare you continue to look away and come here saying that you're doing enough, when the politics and solutions needed are still nowhere in sight.

   2. Visually clear, a sharp image, of high acuity.

      The picture on this TV is crystal clear – you can see every grain of sand!

      • 2007, David Rudd Cycleback, Judging the Authenticity of Photographs: The Basics for Collectors, Cycleback.com, →ISBN, page 111:

        The key is that only the original negative can produce the crystal clearest photographic image.

   3. Very translucent or transparent.
      • 1893, Charles F[orbes] Warner, editor, Picturesque Berkshire, part I (North), Northampton, Mass.: Picturesque Publishing Company; Springfield, Mass.: The W. F. Adams Company, page 84:

        On the lowest level are broad meadow lands, through which wanders a stream of the most crystal clear water imaginable.

      • 1980, AA Book of British Villages, Drive Publications Ltd, page 100:

        Near by, where the crystal clear River Llugwy is crossed by a bridge, stands a small and ancient church built of massive, irregular boulders.

      • 2017 October 4, “Guy Crabb Plumbing & Heating”, in View from Weymouth, Weymouth, page 25:

        It is these beliefs that set Clearview Stoves apart and set their company on a quest to design and build a stove that would set new standards and quite simply be the best. Their quest led to a stove with traditional styling, that is simple to use and highly efficient with a wonderful view of the flames behind crystal clear glass.

      • 2017, Steven Baker, chapter 16, in Colour Sergeant Chesney V.C., Kibworth, Leics.: The Book Guild Ltd, →ISBN, page 132:

        Jimmy and Ravi put together fine silver cutlery, crystal clear glasses and oriental decorated crockery.

   4. Having no clouds.
      • 1882 May 1, C[harles] Piazzi Smyth, Madeira Meteorologic: Being a Paper on the Above Subject Read Before the Royal Society, Edinburgh, on 1st of May 1882, Edinburgh: David Douglas, pages 31–32:

        Whence it comes that even in the crystal clearest weather Madeira’s sunshine spectrum is inordinately full of water-vapour stopped lines, the sun’s direct rays, though to general observation luminous enough, are signally deprived of their proper scorching heat, and the temperature range of the climate is immensely reduced for both the day and the year; […]

      • 1948, Roger Coty Peterson, Birds Over America, New York, N.Y.: Dodd, Mead & Company, page 309:

        Jones Beach Pond on Long Island, so close to New York that the tops of the Empire State and the Chrysler Building can be seen on the horizon on crystal clear days, is one of the best shore-bird resorts I know.

      • 1965, Russ Leadabrand, A Guidebook to the Sunset Ranges of Southern California: […], Los Angeles, Calif.: The Ward Ritchie Press, →LCCN, page 127:

        On crystal clear days, such as those during or just following a Santa Ana windstorm, the Salton Sea can be spotted from this area.

   5. Aurally clear.
      • 1999 July 30, “D’Imperio’s”, in Weekend Mag (Pittsburgh Post-Gazette), Pittsburgh, Pa., page 33:

        There is still space available for the STARFIRE BAND performance featuring the crystal clearest, cleanest Pittsburgh Born and Bred Alto Vocals of the sensational Miss Judi Figel in our Summer Street Dance and Al Fresco Dining (inside if rain) series Music & Dancing 7-11 P.M

      • 2004 March 8, Cameron J. Woods, “‘Bloody lovely’ music: New band worth a little money”, in The Daily Collegian, volume CXIV, number 1, Amherst, Mass.: University of Massachusetts Amherst, page 4, column 2:

        With the slightly nasal, melodic whine of Wooten’s crystal clear vocals this song has a catchy sound to it that guarantees that it has potential to be an ear-bug.

      • 2012, 2012 Engineering & Scientific Catalogue, Jaycar, page 218:

        A truly powerful and versatile unit, crystal clear music is played through a pair of stereo speakers and has RCA line outputs for amplifier or Hi-Fi system integration.

In sense “understanding”, used both of explanations (by speaker) – “Her explanation of integration was crystal clear,” – and of understanding (by listener) “Is this crystal clear in that thick head of yours?”

• pellucid
• plain as day
• see Thesaurus:obvious

• clear as a bell (of sound)

• crystal clearly
• crystally clear