Feast day and Fiesta

Feast day noun - A day designated for feasting.

Fiesta and feast day are semantically related in celebration topic. In some cases you can use "Fiesta" instead a noun phrase "Feast day", when it comes to topics like festivity, fete.

Fiesta noun - A time or program of special events and entertainment in honor of something.

Feast day and fiesta are semantically related in celebration topic. You can use "Feast day" instead a noun "Fiesta", if it concerns topics such as festivity, fete.