The form of the headword is uncertain. It varies between zi/rhs and zi/rh in the Suda mss, and appears to correspond to the Scythian word zi/rin in Lucian, Toxaris 40.6-20, for a Scythian summoned to free a captive by offering ransom. Lebedynsky [see Bibliography] 93-94 and others link it to an East Iranian word for gold: Avestan zaranya-, Khotanese zarîna, Ossetic (syg)zärin.
Not to be excluded is a relationship to the attested word zeira/ for a wide, girdled upper garment (zeta 46, zeta 47; cf. LSJ, Hesychius zeta162 on zirai/, a plural) worn by the Thracians (Herodotus 7.75; Xenophon, Anabasis 7.4.4) and Arabs (Herodotus 7.69). The Thraco-Phrygians were neighbours of the Scythians in the Danube region (cf. epsilon 3019 note 1), and were occasionally confused with them. There was evidently cultural borrowing between the two, perhaps also linguistic. The particular garment may have been widespread in various horse-riding cultures.
[1] This seems to be intended as the Scythian genitive, and appears as such in the Lexica available to Adler as her Ambr(osianum) and L(aurentianum). We may speculate that the form in Lucian is an accusative, implying the verb 'I call for'.
[2] Although the Suda, like Hesychius, has many references to the Scythians, this appears to be the only Scythian headword (if we ignore the possibility of cannabis; cf. kappa 298). Very few Scythian words have been transmitted to us (see Lebedynsky 92-98). Present-day writers (e.g. David Braund in OCD(4) 1335-6) often speak as if the name was attributed loosely by the ancients to different entities, but the simple fact may be that it was an artistic and political culture or alliance of cultures embracing different ethnic and linguistic groups. There are numerous dubious theories that attempt to link the Scythians to the proto-Slavs, the Uralic-Altaic peoples or the Caucasians. It should be borne in mind that Herodotus assigns their origins to Anatolia, and a relationship, at least in cultural terms, to the Anatolians cannot be ruled out.
Scythian as a language in fact appears to have been Indo-European, belonging to the “Northeastern” group of the Iranian subfamily (represented by modern Pashtu in Afghanistan and Pakistan). It was therefore related to other East Iranian languages, including Avestan, Khotanese, Parthian, Bactrian, and Ossetic, which are used to postulate vocabulary and forms of Scythian.