1. A fleet or naval force, especially in ancient Rome.
Usage: historical; often capitalized when referring to a specific Roman fleet
2. In some Protestant churches, a regional governing body or assembly of clergy and elders.
Usage: ecclesiastical; chiefly used in Reformed and Presbyterian traditions

Examples

• The Roman classis patrolled the Mediterranean to protect trade routes.
• Augustus expanded the imperial classis to maintain control over distant provinces.
• The church's classis met quarterly to discuss matters of doctrine and discipline.
• Ancient naval warfare often involved clashing fleets, or classis, in strategic harbors.
• The local classis approved the appointment of the new minister.