blotchnoun/blɒtʃ/

• 1

  An uneven patch of color or discoloration.

  • 1711, Joseph Addison and Richard Steele, The Spectator, London: J. & R. Tonson, 12th edition, Volume I, No. 16, p. 68, […] in healing those Blotches and Tumours which break out in the body […]
  • Since the day in which this reformation began, by how many strange and critical turns has it been perfected and handed down, if not, entirely without spot or wrinkle,—at least, without great blotches or marks of anility.
• 2

  An irregularly shaped area.

  • At Coleman's Hill, the upper beds consist of yellowish, soft, gritty sandstone, containing some small calcareous fragments, a few pebbles of quartz, blotches of red shale, and fragments of sandstone with impressions of stems of plants.
  • His shirt showed big blotches of moisture, and the sweat was rolling in clear drops along the creases in his brown neck.
• 3

  Imperfection; blemish on one’s reputation, stain.

  • 1921, Warren G. Harding, Inaugural address, in Inaugural Addresses of the Presidents of the United States: from George Washington to Barack Obama, Washington, D.C.: U.S. G.P.O., 1989, There never can be equality of rewards or possessions so long as the human plan contains varied talents and differing degrees of industry and thrift, but ours ought to be a country free from the great blotches of distressed poverty.
• 4

  Any of various crop diseases that cause the plant to form spots.

  • The fungus causing blotch lives through the winter in the cankers which it has developed on twigs, water sprouts, and fruit spurs.
  • Blue mold and the black rot fungus are most Commonly found associated with blotch in this way.
• 5

  A bright or dark spot on old film caused by dirt and loss of the gelatin covering the film, due to age and poor film quality.

  • Characteristics of blotches are that they seldom appear at the same spatial location in consecutive frames, they tend to be smooth (little texture), and they usually have intensity values that are very different from the original contents they cover.
  • Films corrupted by blotches are often restored in a two-step approach. The first step detects blotches and generates binary detection masks that indicate whether each pixel is part of a blotch. The second step corrects pixels by means of spatio-temporal interpolation.
• 6

  A dark spot on the skin; a pustule.

• 7

  slangBlotting paper.

blotchverb/blɒtʃ/

• 1

  To mark with blotches.

  • 1770, Arthur Young, A Six Months Tour through the North of England, London: W. Strahan, Volume 2, p. 258, Upon the whole, the spirit and relief of the figures, with the strength of the colouring, render it a most noble picture; and it is not done in the coarse blotching stile, so common to the pieces which pass under the name of Bassan.
  • A straight-edge is placed upon the chalk lines, with the edge next the line slightly raised, and the brush, well filled with colour, drawn along it, just touching the wall, the pressure being never increased, and the brush refilled whenever it is near failing; but great care must be taken that it be not too full, as in that case it will be apt to blotch the line, or drop the colour upon the lower portions of the wall.
• 2

  To develop blotches, to become blotchy.

  • 1878, Arthur Morecamp (pseudonym of Thomas Pilgrim), Live Boys; or, Charley and Nasho in Texas, Boston: Lee & Shepard, Chapter 17, p. 166, […] when a man is going to drive cattle out of the county he has to put a road-brand on them […] It is generally made of letters or figures, or something that won’t cross lines, because where they cross they are apt to blotch and then it’s hard to tell what the brand is and who the animal belongs to.
  • Our waistline will extend a few more inches at least, and our aging skin will blotch and sag.