quadr-, pent-, oct-

12345678910
Across
  1. 2. a flat shape that has eight sides and eight angles
  2. 4. a sea animal that has a soft body and eight long arms
  3. 5. one part of something that is evenly divided into four parts
  4. 6. one part of something that is evenly divided into four parts
  5. 7. a group or set of five
  6. 8. a sports contest for men that consists of five different events
  7. 9. the difference in sound between the first and eighth note on a musical scale
  8. 10. a person who is between 80 and 89 years old
Down
  1. 1. a flat shape that has four sides and four angles
  2. 2. the 10th month of the year
  3. 3. to cause (something) to become four times bigger
  4. 4. a song or piece of music performed by eight singers or musicians
  5. 7. a flat shape that has five sides and five corners