The Spanish word 'calcomanía' (meaning 'decal' or 'transfer picture') comes from the French word 'décalcomanie'. This French term was created by combining 'décalquer' (meaning 'to transfer or copy') with 'manie' (meaning 'mania' or 'passion').

Going further back, 'décalquer' was formed from the prefix 'dé-' (indicating reversal or removal) and 'calquer' (meaning 'to trace'), which itself comes from Latin 'calcare' meaning 'to trace'. The 'manie' portion derives from Greek 'mania' meaning 'madness' or 'passion'.

The word essentially described the 19th century enthusiasm for transferring decorative patterns and pictures, which we now know simply as decals or transfers.

A related Spanish word is 'calcar', meaning 'to trace or copy', which comes from the same Latin root 'calcare'. When you use a 'calcomanía', you are essentially tracing or transferring an image from one surface to another.

English speakers might recognize the second part of 'calcomanía' in words like 'mania', 'maniac', and 'manic', all of which come from the same Greek root 'mania'. While these English words retain the sense of intense mental state or obsession, in 'calcomanía' the '-manía' part just refers to the enthusiasm or passion for the transfer process.

The English word 'decal' is actually a shortened form of 'decalcomania', which was borrowed from the same French word that gave Spanish 'calcomanía'.