Chadwick & Ventris 1973: a portion (of land) enjoyed, beneficiary right; accusative singular neuter
Chadwick & Ventris 1956: "One might have considered translating o-na-to as ὠνητόν (Dor. ὠνατόν) 'bought, buyable', whatever this precisely means in a primitive economy; but the Skt. vasnám suggests that ὠνή (Lesb. ὀννα) should have initial *w-, and a derivation of the Mycenaean term from ὀνίνημι 'bestow a benefit' is more probable."
Chadwick & Ventris 1973: accusative plural
Chadwick, John and Michael Ventris, 1973 Documents in Mycenaean Greek
Chadwick, John and Michael Ventris, 1956 Documents in Mycenaean Greek