The word cardinal is derived from two early Latin terms, cardo and cardinis.

For the past three hundred years, the English translation has rendered these two words as "hinge", to signify that important device that serves as a juncture for two opposing forces and that affords harmony as a result. As a hinge permits a door to hang easily upon a framed portal, so too the cardinals, it was believed, facilitated an early relationship between the theological and governmental roles of the hierarchy of the Church. In actuality, the words cardo and cardinis take on a more profound theological meaning, which sadly, has been lost to the English-speaking world for some three hundred years, in no small part due to the Reformation's attempt to strip any profound theological meaning away from the hierarchy of the Roman Church. Cardo and cardinis should more accurately be rendered as "pivot" or "tenon", two terms that more accurately depict the role of the cardinalate. Upon this pivot, which is a small nail-like device, symbolically hands the relationship between Heaven and Earth, between Christ and His Church on earth.

The role of a cardinal, as well as his title, is ancient. For two centuries prior to the Christian era, Roman society had been organized hierarchically, with senators and patriarchs holding the highest office, each having assistants to carry through on their edicts or decrees. These assistants were originally known as praesides, then pro counsels, and simultaneously prefecti praetoriani. These important second-level civil authorities were soon considered to be the representatives of the "all highest" rulers of Roman society and took on an importance all of their own. Simultaneously, the Church continued to flourish, and its structure clearly mimicked that of the Roman Empire. The original seven assistants chosen by the apostles in Jerusalem passed on, many martyred for their faith. They were replaced, in turn, by others who were consecrated as the need for these special assistants continued to grow alongside the growing infant Church.

By the end of the second century, these select were considered to be an essential part of the Church's hierarchy, yet remained separate from the bishops, priests and deacons. They remained laymen, continuing the external work of the local Church. As their importance grew, they rapidly took on an importance that necessitated a theological understanding of their expanded role in the Church. Quator mundi cardines, a concept meaning the four cardinal, or crucial, points that signify the extremities of the universe and that define the juncture of Heaven to Earth, which is the Church, was applied to the cardinals collectively to theologically define the role of the cardinalatial office. Cardinals were defined, therefore, as the critical supporters of the papacy as early as the mid-third century. By the fourth century, the theology of the cardinalate had taken form, and the title Cardinal was applied to these special consultors to the Bishop of Rome.