Origin: obs. opson(ium), relish (< L < Gr opsōnion, food, provisions < opsōnein, to buy food < opson, meat or any food eaten with bread < o-, together with + *psōn, food, bread, akin to psōmos, mouthful) + -in
See opsonin in American Heritage Dictionary 4
Origin: Latin opsōnāre, to buy provisions (from Greek opsōnein, from opson, condiment, delicacy; see epi in Indo-European roots)
Origin: + -in.
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