The Spanish word 'católico' (meaning 'catholic' or 'universal') comes from Latin 'catholicus', which was borrowed from Ancient Greek 'katholikos' (καθολικός), meaning 'universal'. The Greek word is actually a combination of two parts: 'kata' (κατα) meaning 'down' or 'throughout', and 'holos' (ὅλος) meaning 'whole'. When combined, these elements created the sense of something that is 'according to the whole' or 'universal', which later became associated with the Catholic Church due to its claims of universality.

While 'católico' itself is a common Spanish word, there are related Spanish words that share the Greek root 'holos' (whole), such as 'holístico' (holistic) and 'holocausto' (holocaust). These words all carry the sense of 'wholeness' or 'completeness' from their Greek origin.

English speakers can easily relate 'católico' to the English word 'catholic' (both in its religious sense and its general meaning of 'universal'). Other English words sharing the Greek root 'holos' include 'holistic', 'holocaust', and 'whole'. The 'kata-' element appears in many English words like 'catalog' (originally meaning a complete listing), 'catastrophe' (a complete overturning), and 'category' (a complete division or class).