The Spanish word 'pipián' comes directly from the Nahuatl (Aztec) word 'pipiyani', which referred to a sauce made with pumpkin seeds. This is one of many culinary terms that Spanish borrowed from the indigenous languages of the Americas, as European colonizers encountered new foods and cooking techniques. The word maintained nearly the same pronunciation and meaning as it transitioned from Nahuatl to Spanish, still referring to a sauce made with ground pumpkin seeds, which remains an important element in Mexican cuisine.

Since 'pipián' comes from Nahuatl rather than Latin or Greek roots, there aren't many etymologically related simpler Spanish words. However, in Mexican Spanish you might encounter related culinary terms like 'pepita' (pumpkin seed), though this actually comes from a different etymology (from Latin 'pepita' meaning seed).

There aren't any etymologically related English words since 'pipián' comes from Nahuatl. However, English has borrowed this word directly as 'pipian' to refer to the same Mexican sauce, though it's much less commonly used in English than in Spanish. English speakers might be more familiar with the term 'mole verde' (green mole), which is sometimes used to describe this type of sauce.