Likewise or similarly in other lexica; references at Photius upsilon334 Theodoridis. The headword is nominative plural, either quoted from somewhere in that form or generated by an oblique case.
The adjective is attested as an attribute of Zeus (cf. under omicron 251), employed by e.g. Hesiod (web address 1), Bacchylides (web address 2), and Aristophanes (web address 3); also used by Pindar, referring to the height of Mount Parnassus.