The Spanish word 'macha' comes directly from Mapuche, an indigenous language of Chile and Argentina. In both languages, it refers to an edible mollusk species (Mesodesma donacium) that is native to the Pacific coast of South America. This is one of many words that Spanish acquired from indigenous American languages, particularly for local flora and fauna that were unknown to European Spanish speakers before colonization.

Since 'macha' comes from Mapuche and entered Spanish specifically to name this particular mollusk species, there aren't any simpler or more common Spanish words that share its etymology.

There aren't any etymologically related English words since 'macha' comes from Mapuche, an indigenous South American language that had no historical contact with English. English speakers might encounter this word only in the context of South American cuisine or marine biology.