a) In a weft-knitted fabric, a defect that consists of ill-defined areas of varying density attributable to the use of yarn of irregular thickness.
b) In webs and slivers, a defect that consists of ill-defined areas of varying density.
c) In a dyed fabric, a defect that consists of random, faintly defined areas of varying density.
d) In a bleached fabric, a defect that consists of opaque patches, usually visible only in transmitted light.