1. Godan verb with 'ku' ending, Intransitive verb

   to open (e.g. doors)

   esp. 開く

   ぐいと押すとドアは開いた。

2. to open (e.g. business, etc.)

   esp. 開く

3. to be empty

   esp. 空く

4. to be vacant; to be available; to be free

   esp. 空く

5. to be open (e.g. neckline, etc.)

   esp. 明く

6. to have been opened (of one's eyes, mouth, etc.)

   esp. 明く

7. to come to an end

   esp. 明く

8. Godan verb with 'ku' ending, Transitive verb

   to open (one's eyes, mouth, etc.)

   esp. 明く

9. Godan verb with 'ku' ending, Intransitive verb

   to have a hole; to form a gap; to have an interval (between events)

   see 穴が開く

Also written 空く【あく】aku、明く【あく】aku