A holiday is a special day for religious or cultural reasons – such as Christmas,
Easter, New Year’s Eve, and your country’s Independence Day. Some holidays are
also official days off from work, and others are not.
A vacation is when you take multiple days off from work/school to relax and/or
travel. However, American English speakers call this a vacation and British English
speakers call this a holiday:
▶️ My parents are on vacation in Asia. (American English)
▶️ My parents are on holiday in Asia. (British English)