Charles Buck Theological Dictionary 
Synod of; a national synod, summoned by authority of the states-general, the provinces of Holland, Utrecht, and Overysel excepted, and held at Dort, 1618. The most eminent divines of the United Provinces, and deputies from the churches of England, Scotland, Switzerland, Bremen, Hessia, and the Palatinate, assembled on this occasion, in order to decide the controversy between the Calvinists and Arminians. The synod had hardly commenced its deliberations before a dispute on the mode of proceeding, drove the Arminian party from the assembly. The Arminians insisted upon beginning with a refutation of the Calvinistic doctrines, especially that of reprobation; whilst the synod determined, that, as the remonstrants were accused of departing from the reformed faith, they ought first to justify themselves by scriptural proof of their own opinions. All means to persuade the Arminians to submit to this procedure having failed, they were banished the synod, for their refusal. The synod, however, proceeded in their examination of the Arminian tenets, condemned their opinions, and excommunicated their persons: whether justly or unjustly, let the reader determine. Surely no one can be an advocate for the persecution which followed, and which drove these men from their churches and country into exile and poverty. The authority of the synod was far from being universally acknowledged either in Holland or in England. The provinces of Friesland, Zealand, Utrecht, Guelderland, and Groningen, could not be persuaded to adopt their decisions; and they were opposed by king James I. and archbishop Laud, in England.
Watson's Biblical & Theological Dictionary 
The Nuttall Encyclopedia 
town on an island in the Maas, in the province of South Holland, 12 m. SE. of Rotterdam; admirably situated for trade, connected as it is with the Rhine as well, on which rafts of wood are sent floating down to it; is famous for a Synod held here in 1618-19, at which the tenets of Arminius were condemned, and the doctrines of Calvin approved of and endorsed as the doctrines of the Reformed Church.