Epic noun, from ὀαρίζω : LSJ entry at web address 1 (probably in error, see below and notes and bibliography in Omicron 2).
The definition is an obvious error for γυναικοπληθὴς ὅμιλος , a phrase used at Aeschylus, Persae 121 of women shouting ὀά . It has been entered by error under this Headword, instead of under the cry, a Headword apparently lost in Suda but found in the scholia ad loc. (and elsewhere), and as Hesychius omicron6.
It is the title assigned to Theocritus - or [Theocritus] - 27. Otherwise the word is used only in Homer's Iliad, twice of the rapid exchanges in battle (13.291, 17.228, see web addresses 2 and 3), once of one of the pleasures caused by the power of Aphrodite's breast band (14.216, web address 4). It is well translated by Robert Fagles (The Iliad of Homer, 1990) as "give-and-take". See Omicron 2, Omicron 3, for the etymology and semantic history of the word, and the reasons why it sometimes refers to the give-and-take of lovers.