The Spanish word 'pulpo' (meaning 'octopus') comes from the Latin word 'polypus', which itself was borrowed from Ancient Greek 'πολύπους' (polypous). The Greek word is a compound of two elements: 'πολύς' (polys) meaning 'many' and 'πούς' (pous) meaning 'foot', literally describing the octopus as a 'many-footed' creature. Over time, as the word passed from Greek through Latin into Spanish, the pronunciation simplified to become 'pulpo'.

While 'pulpo' itself is a relatively simple and common Spanish word, there are related Spanish words that share the 'poly-' prefix meaning 'many', such as 'polígono' (polygon) and 'polideportivo' (sports center). However, in these cases, the connection might not be immediately helpful for remembering the meaning of 'pulpo'.

English speakers can easily connect 'pulpo' to several related English words. The most direct cognate is 'polyp', which comes from the same Greek root. While 'polyp' has taken on a different meaning in English (referring to a type of sea creature or a medical growth), it shares its etymology with 'pulpo'. The Greek elements are also very productive in English: 'poly-' appears in many words meaning 'many' (like 'polygon', 'polyglot'), and '-pus' from 'pous' (foot) appears in words like 'octopus' and 'tripod' (three-footed).