CCC 187 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”.
CCC 188 The Greek word symbolon meant half of a broken object, for example, a seal presented as a token of recognition. The broken parts were placed together to verify the bearer’s identity. The symbol of faith, then, is a sign of recognition and communion between believers. Symbolon also means a gathering, collection or summary. A symbol of faith is a summary of the principal truths of the faith and therefore serves as the first and fundamental point of reference for catechesis.