[1] The primary headword, possibly (though not necessarily) extracted from somewhere, is the present active infinitive of the verb o(rme/w, I am moored, I lie at anchor; see LSJ s.v. The distinction implied here by the lexicographer, between a ship drawn up out of the water and one still afloat but riding at anchor, is not borne out by usage.
[2] The second and third of these elements appear again at omicron 603. Adler also cites Lexicon Ambrosianum 547 for comparison. [In her critical apparatus Adler notes that ms S gives this verb as o(rma/zw -- a late form of a(rmo/zw, according to LSJ.]