The Spanish word 'sombra' (meaning 'shadow') comes from the Vulgar Latin term 'subumbra', which literally meant 'under the shadow'. This Vulgar Latin word was formed by combining two Latin words: 'sub' meaning 'under' and 'umbra' meaning 'shadow'. Over time, 'subumbra' evolved phonetically to become the modern Spanish 'sombra', with the 'u' sounds merging and simplifying.

A common related Spanish word is 'sombrilla' (umbrella or parasol), which is essentially a tool for creating shade or shadow. Similarly, 'sombrero' (the wide-brimmed hat) gets its name from its function of providing shade for the wearer. Both these words are easier to remember when you understand their connection to 'sombra'.

The English word 'umbrella' comes from the same Latin root 'umbra' (shadow). Originally, umbrellas were used for shade from the sun rather than protection from rain. Another related English word is 'umbra', which is used in scientific contexts to refer to the darkest part of a shadow, especially in astronomy when discussing eclipses. The word 'somber' also comes from this same root, as it originally referred to being dark or shadowy before evolving to describe a serious or gloomy mood.