開く

1. Origins, structure, and basic meaning

• Structure: 開く is read あく here and is an intransitive verb for a door opening or a shop beginning business.
• Basic usage: It is used when waiting for train doors to open or stating a shop's opening time.

2. Common pitfalls and similar expressions

• Compared with 開ける
  • 扉が開く describes the change of a door opening. 扉を開ける describes someone opening the door; 開ける is read あける here.