The Spanish word 'espada' (meaning 'sword') traces its origins back to ancient Greek through Latin. It comes from the Latin word 'spatha', which referred to a long, broad sword commonly used in the late Roman Empire. The Latin term itself was borrowed from the Greek word 'σπάθη' (spathe), which described a broad blade of a sword. As the word made its way into Spanish, it underwent a common Spanish phonological development where an 'e' was added at the beginning of words that started with 's' + consonant (s + p in this case), resulting in 'espada'.

A related Spanish word is 'espadachín' (swordsman), which is derived directly from 'espada'. Another related term is 'espadaña', which refers to a type of cattail plant - named so because its long, flat leaves resemble the blade of a sword.

The English word 'spade' (both the gardening tool and the playing card suit) is actually a cousin of 'espada', as it also derives from the Latin 'spatha'. The connection becomes clearer when you consider that both a sword and a spade have similar flat, blade-like shapes. Another related English word is 'spatula', which also comes from the same Latin root, referring to a broad, flat implement.