The Church is One, Holy, Catholic and Apostolic
From the Catechism of the Catholic Church, Simplified
The Four Essential Features (811-812)
One, holy, catholic, and apostolic are the four essential features of the Church. They do not belong to the Church but to Christ, who makes the Church one, holy, Catholic, and apostolic.
Although faith alone recognizes their divine source, their historical manifestations speak clearly to human reason. The Church's "marvelous propagation, eminent holiness, Catholic unity, and invincible stability give an irrefutable witness of her divine mission" (First Vatican Council).