Gloss: ‘arrow’ (item 35 in Bjørn 2017)
Attestations: (?)Hit. isḫuwa(i)- ‘to throw, scatter, pour’; (?)Irish io-dhan ‘spear’, (?)Welsh eog ‘salmon’; Gr. ἰός; Ved. iṣu-, Av. išu-.
Notes: The Irish form, not traditionally connected with this group, has been proposed by Mann (1984: 434), but the accompanying Celtic comparanda definitely do not favor the proposition semantically. Mayrhofer ventures the Hittite connection (1988: 200), but faces opposition by Kloekhorst who prefers to consider the initial i- epenthetic and thus ascribes it to an earlier un-metathesized variant *sh2u– to the verb traditionally reconstructed *suh2– to rain’ (2008a: 396ff.). It seems, however, that both solutions could work semantically as well as formally (cf. Kimball 1999: 143). If the distribution is limited to Graeco-Aryan, it can hardly qualify as a candidate for the oldest strata of PIE, and may alternatively be an innovation to the verbal root *h1eish2- ‘set in motion’, as suggested by Mallory & Adams (1997: 78), notably only attested in Graeco-Aryan.
[ADD: ~ Georgian-Zan *isar– ‘arrow’ > Georgian isar-, Laz isiǯ̩ ‘arrow’, Megrelian isinǯ̩ ‘spear, lance; competition’]
Discussion: If, indeed, a foreign element in (P)IE, as suggested by Dolgopolsky (1987: 15, 1989: 7), the regional distribution suggests later transfer, comparable to *pelekû – ‘axe’ (item 102) into Graeco-Aryan or late PIE. There seems to be a dearth of Afro-Asiatic cognates (cf. Orel Stolbova 1995 and Militarev 2006 s.v. ‘arrow’), which questions its age in Semitic, too, and an unattested third source may be posited, but this seems unnecessarily complicated, and the item may well represent a borrowing from Semitic into late PIE.
[ADD: Cf. also Georgian-Zan *isar- ‘arrow’ (Bouda 1950: 301), but see Klimov (1998: 82) for the formal likelihood of a native formation. Svan cxwi ‘arrow’ (Gudjedjiani & Pamaitis 1985: 277) apparently unrelated]