The Spanish word 'cayena' (meaning cayenne pepper) has an interesting dual etymology. It comes from both the Tupi-Guarani word 'kyinha' meaning 'hot pepper' and from 'Cayenne', the capital city of French Guiana. This is because cayenne peppers were commonly grown and traded in the Cayenne region, and the indigenous Tupi-Guarani people of South America had their own word for this spicy pepper. The name became standardized in Spanish as 'cayena', preserving both these historical connections.

There aren't many common Spanish words that are etymologically related to 'cayena', as it comes from a very specific geographical and indigenous language source. The word stands somewhat alone in Spanish vocabulary.

In English, we use 'cayenne' to refer to the same spicy pepper. The English word maintains a closer spelling to the original French city name 'Cayenne'. When you see 'cayenne pepper' on a spice bottle or in a recipe, you're using a word that shares the exact same origins as the Spanish 'cayena'.