The Spanish word 'mamila' comes directly from the Latin word 'mamilla', meaning 'nipple' or 'teat'. This is a straightforward inheritance where both the form and meaning have remained remarkably stable from Latin to modern Spanish.

This word is related to other common Spanish words in the same semantic family, such as 'mama' (breast), 'mamar' (to breastfeed), and 'mamífero' (mammal). All these words share the same Latin root relating to nursing and breast-feeding.

English speakers might recognize the connection to words like 'mammal', 'mammary', and 'mammogram', which all derive from the same Latin root. These words all relate to breasts and nursing, which is the defining characteristic of mammals as a class of animals.