Want to schedule plans with friends? Make a reservation at a restaurant or hotel? Book travel plans? You’ll need to know the days of the week.

This is an essential step in mastering the Korean language.

Here are the days of the week in Korean:

You may notice that each weekday in Korean ends in “요일”. 일 and 요일 both mean “day,” with 요일 being used more specifically for days of the week.

The first syllable of each word is related to nature or astronomy, pictured above. Here’s a breakdown:

일 can mean either “sun” or “day” depending on the context.