八日

1. Origins, structure, and basic meaning

• Structure: 八日, read ようか, means either eight days or the eighth day of a month.
• Basic usage: 八日がたった counts elapsed days; 来月の八日に identifies a calendar date.

2. Common pitfalls and similar expressions

• Eight-day duration and eighth-day date
  • Elapsed-time wording selects duration, while 来月の...に selects a date; both use the reading ようか.