The Spanish word 'bigote' (meaning 'moustache') has an interesting etymology that traces back to Latin roots. It comes from Old French 'bigot', which itself derived from Latin 'bicostis' meaning 'two-sided'. This Latin word was formed by combining two elements: the prefix 'bi-' meaning 'two' and 'costa' meaning 'side' or 'rib'. The evolution from meaning 'two-sided' to referring to a moustache likely came about because a moustache appears on both sides of the face, creating a symmetrical, two-sided appearance.

Some related Spanish words that share the 'bi-' prefix include 'bilateral' (two-sided), 'bicicleta' (bicycle), and 'bilingüe' (bilingual). The 'costa' element appears in Spanish words like 'costa' (coast) and 'costal' (relating to the ribs).

English speakers might recognize the Latin elements in words like 'bicycle' (two wheels), 'bilateral' (two-sided), and 'coastal' (relating to the side or edge of land). Interestingly, while 'bigote' came to Spanish through French 'bigot', the English word 'bigot' (meaning a prejudiced person) is believed to have a different etymology despite the similar spelling.