Usually unseparated from Akk. peṣû and Arb. byḍ ‘to be white’, which are likely to form a different root *payṣ̂- including also Gez. beṣā, bəṣā ‘yellow’, byṣ ‘to become white, yellow’ [LGz. 116] (ṣ being a graphic variant of the expected *-ḍ?), Amh. bəč̣a, bič̣a ‘yellow’ [K 950] and Tgr. bäyyäṣä ‘to be bright, brilliant’ [LH 295].
According to a widespread opinion, goes back to the color term
*byṣ̂ ‘to be white, bright, yellow’. If this etymology is correct, we are faced with a PCS semantic innovation, but the opposite way of derivation (“egg” > “white”) has also been suggested (F. Rosenthal apud CDG 116). In any case, this wide-spread opinion formulated by Leslau as «the root byṣ 〈erroneously for byḍ. - A. M. /L. K.〉 ‘become white’ is the origin of the noun ‘egg’ in ... various Semitic languages» [LGz. 116] should probably be revised in the light of W. Chad. parallels: Geji mbuuŝì, Buli mbiŝ, Tule mbòòŝə, Zaar buùŝ ‘egg’ [Stolb. 1996 122] (reconstructed as *m-buy/ˀVŝ [ibid.] corresponding to Afras. *buyač̣ after [OS 86]).
In HSED 86, PCS *bayŝ-̣ at- has been compared to hypothetical West Chadic cognates, which would mean that the PCS term is a retention from PAA. Cf.