The headword is the aorist middle infinitive of the verb o)/rnumi; see generally LSJ s.v. It occurs in Homer, Iliad 8.474 (web address 1). See also omicron 555.
[1] The gloss is the aorist passive infinitive of the verb diegei/rw (delta 893); see LSJ s.v. The headword receives the same gloss in ps.-Zonaras 1470.3 and (according to Adler) the unpublished Ambrosian Lexicon (517), and a similar one in the scholia to Homer loc.cit and in Etymologicum Magnum 631.6.