The Spanish word 'marisco' (meaning 'seafood') comes from combining two elements: the Spanish word 'mar' (meaning 'sea') and the adjectival suffix '-isco'. The word 'mar' itself derives from the Latin word 'mare', which also meant 'sea'. The suffix '-isco' was added to create a word specifically referring to edible creatures from the sea, thus giving us 'marisco' to mean seafood or shellfish.

The most obvious related Spanish word is 'mar' meaning 'sea', which is much more basic and common. You'll find this root in many other Spanish words like 'marino' (marine), 'marinero' (sailor), and 'marítimo' (maritime). Understanding that 'marisco' literally means something like 'sea-ish' or 'of the sea' can help remember its meaning of seafood.

While English 'marine', 'maritime', and 'marina' all share the same Latin ancestor 'mare' with Spanish 'marisco', perhaps the most interesting connection is with the word 'marsh'. Though it might not seem obvious at first, 'marsh' also comes from the same Indo-European root that gave Latin 'mare', all referring to bodies of water. The English word 'mere' (meaning a lake or pond) is another related term that preserves this ancient connection to bodies of water.