The Spanish word 'mitología' (mythology) comes from Latin 'mythologia', which was borrowed from Ancient Greek 'mythologia' (μυθολογία). The Greek word is a compound of two parts: 'mythos' (μῦθος) meaning 'story or myth' and 'logos' (λόγος) meaning 'study or discourse'. So literally, mythology means 'the study or discourse of stories/myths'.

The word underwent minimal changes as it passed from Greek through Latin into Spanish, mainly just adapting to Spanish spelling conventions where 'y' became 'i' and 'th' became 't'.

Some related Spanish words include 'mito' (myth), which comes from the same Greek root 'mythos'. You might also recognize the '-logía' ending in many other Spanish words like 'biología' (biology), 'psicología' (psychology), or 'tecnología' (technology) - all of these come from the same Greek root 'logos' meaning 'study of'.

The English word 'mythology' is a direct cognate of Spanish 'mitología', as they both come from the same Greek source. Other related English words include 'myth' (from Greek 'mythos') and words ending in '-logy' like 'biology', 'psychology', etc. (from Greek 'logos'). The main difference is that English preserved more of the Greek spelling with 'y' and 'th', while Spanish adapted the spelling to match its pronunciation rules.