skewbald adj.

c. 1300, ballede, "wanting hair in some part where it naturally grows," of uncertain origin. Perhaps with Middle English -ede adjectival suffix, from Celtic bal "white patch, blaze" especially on the head of a horse or other animal (from PIE root *bhel- (1) "to shine, flash, gleam").

Compare, from the same root, Sanskrit bhalam "brightness, forehead," Greek phalos "white," Latin fulcia "coot" (so called for the white patch on its head), Albanian bale "forehead." But connection with ball (n.1), on notion of "smooth, round" also has been suggested, and if not formed from it it was early associated with it. Middle English Compendium says it probably was formed on the root of ball, and compares Old Danish bældet.

Sometimes figurative: "meager" (14c.), "without ornament" (16c.), "open, undisguised" (19c.). Of automobile tires with worn treads, by 1930. Bald eagle is attested by 1680s; so called for its white head.

c. 1400, "turn aside, take an oblique course, run obliquely or at an angle," also "escape," intransitive senses now archaic or obsolete, from Old North French eskiuer "shy away from, avoid," Old French eschiver (see eschew; also compare shy (adj.)).

The transitive sense of "turn (something) aside, give oblique direction to" is attested from 1570s. The meaning "depict unfairly" is recorded by 1872, on notion of being "give oblique direction to," hence "to distort, to make slant"(compare bias, also an image of obliqueness). The statistical sense dates from 1929. Related: Skewed; skewing.

The adjectival meaning "slanting, turned to one side" is recorded from c. 1600, from the verb; the noun meaning "a slant, a deviation" is attested by 1680s.