曜日

1. Origins, structure, and basic meaning

• Structure: 曜日(ようび) means a named day of the week, such as Monday or Tuesday.
• Basic usage: It is used to check a trash collection schedule or which day of the week suits a shared meal.

2. Common pitfalls and similar expressions

• Asking about a day of the week or date
  • 何曜日(なんようび) asks which day of the week it is.
  • This differs from 何日(なんにち) when asking for a calendar date.
• A day of the week as a condition
  • 何曜日なら means on which day of the week the following action would be possible, treating that day as a condition.