I.an interchange of words for purposes of conciliation, Soph., Eur.: absol. a reconciliation, making of peace, Thuc.: pl. a treaty of peace, Xen.
2.generally, commerce, intercourse, Eur.
II.intervention, δαιμόνων ξυναλλαγαῖς by special interventions of the deities, Soph.; νόσου ξυναλλαγῇ by intervention of disease, id=Soph.: generally, the issue of intervention, a contingency, incident, id=Soph.; ὀλεθρίαισι συναλλ. with destructive issues, id=Soph.