1. to open; to undo; to unseal; to unpack

2. to bloom; to unfold; to spread out

3. to open (for business, e.g. in the morning)

4. to be wide (gap, etc.); to widen

5. to hold (meeting, party, etc.); to give; to open

6. to found (nation, dynasty, sect, etc.); to open (a new business); to set up; to establish; to start

7. to open (ports, borders, etc.)

8. to open (an account)

9. to open up (new land, path, etc.); to clear; to develop

10. to open (a file, etc.)

11. to extract (root); to reduce (equation)

12. to cut open (fish) (as 魚を開く)

13. to change (kanji into hiragana)

14. to flare (e.g. skirt)

15. to slacken (into a poor posture) (as 体が開く, 肩が開く, etc.)

16. to extend (Usually kana, usu. ヒラく)