The most cardinal rule of all that the manager, Mr. Jones, used in his business was to say "THANK YOU" to the people in his office when they did good work.2. Relating to numerical quantities: Examples of cardinal numbers include one, two, three, four, etc. in comparison to ordinal numbers (first, second, third, etc.) that indicate relative positions.
The teacher had a cardinal number of 30 pupils in her class.3. Pertaining to a strong red color, like that of the robes of certain ecclesiastical people: In the early Catholic Church, some of the bishops and presbyters, or priests, were designated cardinal bishops and cardinal priests; all of whom exercised important functions and much depended on their services.
In time, from these developed into the "College of Cardinals" as we know it now.
The vestments, or ceremonial garments, of these dignitaries are red, and what we call cardinal red is a well-known color.