big

1. Origins, structure, and basic meaning

• Structure: 大 means big; its on-readings include だい and たい, and its kun-readings include おおきい.
• Basic usage: 大きい(おおきい) describes size, while 大人 means an adult.

2. Common pitfalls and similar expressions

• Size and an age category
  • 大人 is read as a whole word, おとな. It identifies an adult age category rather than a physically large person.
  • 大きかった is the past form meaning was big or bigger. In the shoe comparison, it describes a difference in size.