[1] The primary headword is aorist of de/rw, third person plural. Same glossing (of a simple verb -- cf. delta 123, delta 266 -- by a compound) in other lexica, and see also the scholia to Homer, Iliad 1.459, from where the headword is evidently quoted.
[2] This distinction is reversed in ps.-Zonaras s.v., who claims that e)/deiran with the diphthong means "they hit," and glosses e)/dhran with the compound e)ce/dhran. But either way, it appears that the form with eta -- not registered in LSJ -- is merely a variant (or misspelling?) of that with epsiloniota. The only independent attestation of e)/dhran itself is in Origen's Scholia on Matthew (PG 17.301.5-7): profh=tai, oi(=s to\n me/n e)/dhran, w(s *Mixai/an, pata/cantos e)pi\ siago/na *Sedeki/ou, to\n de\ a)pe/kteinan, w(s *Zaxari/an. (This episode where the (minor) prophet Micaiah is struck on the cheek occurs in 3 Kingdoms [1 Kings] 22.24 LXX.) See generally LSJ s.v. de/rw II for its 'colloquial' use, attested from Aristophanes onwards, as cudgel, thrash.