The Spanish word 'dinero' (money) comes from the Latin word 'denarius', which was the name of a Roman coin worth ten asses. The 'denarius' itself gets its name from the Latin word 'deni' meaning 'each ten', which in turn comes from 'decem' meaning 'ten'. This etymology reflects how the Roman denarius coin system, based on the number ten, eventually evolved into a general term for money in Spanish.

The word 'dinero' is one of the most basic and common words in Spanish vocabulary, so there aren't many simpler related Spanish words. However, you might encounter derivatives like 'dinerillo' (small amount of money) or 'adinerado' (wealthy), which are built from the base word 'dinero'.

The English word 'denier' (a small French coin used in medieval times) and 'denarius' (when referring to the ancient Roman coin) share the same Latin root as 'dinero'. Additionally, the English word 'denary' (relating to the number ten) comes from the same ultimate Latin root 'decem'. The word 'decimal' is another English relative, also derived from 'decem', showing the connection between the number ten and these monetary terms.