biasyoudaoicibaDictYouDict[bias 词源字典]
bias: [16] English acquired bias from Old French biais, but its previous history is uncertain. It probably came via Old Provençal, but where from? Speculations include Latin bifacem ‘looking two ways’, from bi- ‘two’ and faciēs ‘face’, and Greek epikársios ‘oblique’. When the word first entered English it meant simply ‘oblique line’, but by the end of the 16th century it was being applied more specifically to the game of bowls, in the sense of the ‘bowl’s curved path’, and also the ‘unequal weighting given to the bowl in order to achieve such a path’.

The modern figurative senses ‘inclination’ and ‘prejudice’ derive from this.
[bias etymology, bias origin, 英语词源]
bias (n.)youdaoicibaDictYouDict
1520s, from French biais "slant, slope, oblique," also figuratively, "expedient, means" (13c., originally in Old French a past participle adjective, "sideways, askance, against the grain"), which is of unknown origin, probably from Old Provençal biais, with cognates in Old Catalan and Sardinian; possibly from Vulgar Latin *(e)bigassius, from Greek epikarsios "athwart, crosswise, at an angle," from epi- "upon" + karsios "oblique," from PIE *krs-yo-, from root *(s)ker- (1) "to cut" (see shear (v.)). It became a noun in Old French. "[A] technical term in the game of bowls, whence come all the later uses of the word" [OED]. Transferred sense of "predisposition, prejudice" is from 1570s in English.
For what a man had rather were true he more readily believes. Therefore he rejects difficult things from impatience of research; sober things, because they narrow hope; the deeper things of nature, from superstition; the light of experience, from arrogance and pride, lest his mind should seem to be occupied with things mean and transitory; things not commonly believed, out of deference to the opinion of the vulgar. Numberless in short are the ways, and sometimes imperceptible, in which the affections colour and infect the understanding. [Francis Bacon, "Novum Organum," 1620]
bias (v.)youdaoicibaDictYouDict
1620s, literal and figurative, from bias (n.). Related: Biased; biasing.