The headword -- probably quoted from Homer, Iliad 18.236 (web address 1), where Achilles first catches sight of the dead Patroclus -- is a neuter noun in the dative singular. See generally LSJ s.v. fe/retron = fe/rtron, and further below.
[1] The alternative spelling of the headword, fe/retron, is identically glossed in the Synagoge; cf. Hesychius s.v. e)m fere/trw|, Photius Lexicon s.v. *fere/trwi, Etymologicum Magnum 790.55 (Kallierges) s.v. fere/trw|, ps.-Zonaras s.v. *)en fere/trw|, and Lexica Segueriana 404.27. Adler also cites the Etymologicum Genuinum. [In her critical apparatus Adler reports that ms G transmits nekroforw=n: for the burying of the dead.]
[2] From the scholia to Homer, Iliad 18.236 (see above). One sense of the second substantive here is a gurney -- thus the same as the headword -- but in addition it can mean sedan-chair and has yet another alternative spelling, fo/rion; see LSJ s.v. forei=on. [Here mss GM, Adler reports, omit the conjunction kai\: the foreion is a fertron.]
[3] An approximation and abridgement of Polybius 8.29.4-6 (where in fact the alternative spelling fere/trw| is transmitted: web address 2). It recounts the ruse by which Philemenus betrayed Tarentum (*ta/ras; present-day Taranto in Puglia, S Italy; Barrington Atlas, map 45 grid F4; OCD(4) s.v., tau 112, tau 113) to Hannibal (OCD(4) s.v. and alpha 2452). The young hunter, a Tarentine native, brought a killed wild boar to the city gates at night (cf. alpha 3976 for a related passage) and fooled the guard into opening the gates to him and his fellows (cf. mu 632, again) during the Second Punic War (218-201 BCE) in 213-12; Walbank pp. 100-6. [Adler reports that mss AF transmit ui(o\n: his son, not the boar, and that ms G tries nu=n, now.]
[4] Prior to the Suda, in fact, fe/reqron is not attested. For a later instance of this form see Eustathius, Commentary on Homer's Odyssey 1.155.11 (C12 CE). See also phi 210.