four

1. Origins, structure, and basic meaning

• Structure: 四 represents the number four. Readings such as し, よん, and よっ occur depending on the word.
• Basic usage: 四月(しがつ) means April, 四つ(よっつ) means four items, and 四日(よっか) can mean either the fourth day of a month or a period of four days.

2. Common pitfalls and similar expressions

• A date and an elapsed period
  • 来月の四日 is the fourth of next month. 四日が過ぎた means four days have passed, so the same reading よっか is interpreted through its context.