The Spanish word 'urinario' comes from the Latin word 'urinarius', meaning 'relating to urine'. This Latin word was formed by combining two parts: the noun 'urina' (meaning 'urine') and the suffix '-arius' (meaning 'relating to' or 'connected with'). When Latin evolved into Spanish, 'urinarius' naturally developed into 'urinario', maintaining both its form and meaning as something related to urine or a place for urination (a urinal).

A simpler related Spanish word is 'orina' (urine), which also comes from the Latin 'urina'. The word 'orinar' (to urinate) is also part of this word family. These words are more commonly used in everyday Spanish and share the same Latin root as 'urinario'.

English speakers can easily connect 'urinario' to several similar English words that share the same Latin origin, such as 'urinal', 'urine', and 'urinary'. All these words preserve the basic meaning related to urine and urination, making it easier to remember the Spanish word. The English words maintain an even closer spelling to the original Latin than the common Spanish 'orina'.