Across
- 4. a shape with nine sides
- 5. sea creature with eight tentacles
- 8. music for four parts
- 9. a group of three literary pieces
- 10. happening every seven years
- 12. a period of ten years
- 13. the only one of its kind
- 15. sports competition with ten events
- 17. the number 1 followed by 18 zeros
Down
- 1. someone between the age of 60 and 69
- 2. able to speak two languages fluently
- 3. shared by all
- 6. navigation tool for knowing latitude and longitude
- 7. a musical interval of eight tones
- 10. a group of seven people or things
- 11. a competition of swimming, cycling, running
- 14. recurring every ninth day
- 16. happening every two weeks
- 17. to multiply by four