一回

1. Origins, structure, and basic meaning

• Structure: 一回, read いっかい, means one occurrence or one time.
• Basic usage: It is used to state a frequency within a day or to describe hearing an explanation once.
  • この薬は一日一回飲んでください。

2. Common pitfalls and similar expressions

• The change in the reading of 一
  • The reading いち of 一 changes to いっ in 一回, with a small っ.