The headword occurs, in the nominative plural, in reference to shelter for ships at Homer, Odyssey 5.404 (web address 1), and the gloss is found in commentary on that passage, where it is often made clear that the reference is to coastal landforms that provide safe harbor for ships, rather than to any covering overhead; cf. Apollonius Sophistes, Homeric Lexicon 75.1, Etymologicum Gudianum (Additamenta) 512.26-7; ps-.Zonaras 803.6; contrast Hesychius epsilon5449. But the earliest attestation in the singular (although accusative) is Apollonius Rhodius, Argonautica 4.1640, and it is possible that the Suda's entry is based on the scholia to that passage, where we also find the same gloss. See also under upsilon 436.
Adler also cites Ambrosian Lexicon 1453.