What is a Classis?
Classis comes from the ancient Latin word "classis," and in one of its uses referes to a "fleet of ships." The original purpose of a classis was largely the- logistical movement of personnel and support; and to keep open communication routes across great expanses of water, or landscape separated by water.
During the period following the Protestant Reformation, the Reformed branch of that movement borrowed the Latin term to describe a group of pastors and elders having jurisdiction over churches in a particular district, or region. In essence, the work of those early classes(plural form of classis) was the same- keeping lines of communication open while providing "logistical support" for the churches regarding theology, outreach, and denomination needs.
Today, Classis is a "middle management governing tool" of the Christian Reformed Church in North America representing both the denomination as a whole and individual churches of a particular region; but even more- each Classis is an enabler to churches within its region providing spiritual, physical, and financial support.
*Follow this link for more information on the Classis: https://www.crcna.org/welcome/christian-reformed-church-governance/classis