The Spanish word 'daltónico', meaning 'color blind', comes from the surname of John Dalton (1766-1844), an English chemist and physicist who was himself color blind. Dalton was one of the first scientists to study and publish research about color blindness, which led to this condition being named after him. The Spanish word combines his surname 'Dalton' with the Spanish adjectival suffix '-ico' to create the term for someone who is color blind.

While 'daltónico' itself is a relatively straightforward term, the suffix '-ico' is commonly used in Spanish to form adjectives, appearing in many simpler words like 'básico' (basic), 'público' (public), and 'científico' (scientific).

In English, we use the term 'Daltonism' as a less common synonym for color blindness, also derived from John Dalton's name. The condition is more commonly referred to as 'color blindness' in English, while Spanish predominantly uses 'daltonismo' or 'daltónico'.