From the beginning, the apostolic Church expressed and handed on her faith in brief formulae normative for all.But already very early on, the Church also wanted to gather the essential elements of her faith into organic and articulated summaries, intended especially for candidates for Baptism:
This synthesis of faith was not made to accord with human opinions, but rather what was of the greatest importance was gathered from all the Scriptures, to present the one teaching of the faith in its entirety. and just as the mustard seed contains a great number of branches in a tiny grain, so too this summary of faith encompassed in a few words the whole knowledge of the true religion contained in the Old and the New Testaments.
Such syntheses are called “professions of faith” since they summarize the faith that Christians profess. They are called “creeds” on account of what is usually their first word in Latin: credo (“I believe”). They are also called “symbols of faith.
From the Catechism of the Catholic Church 185-187