This noun designates the cultivated or garden olive tree, in contrast to the wild olive (agrielaios). In Romans 11:24, Paul describes Gentiles as branches from a wild olive grafted 'contrary to nature' into a cultivated olive tree (kallielaion). The metaphor is botanically backwards—normally one grafts cultivated stock onto wild rootstock, not the reverse. Paul's point is precisely the unnaturalness of Gentile inclusion: God has done something unexpected and gracious, grafting wild branches into Israel's cultivated tree to share in the 'rich root' of the patriarchs.