Related Clues:

• Prefix with -hedron
• Numerical prefix
• Prefix with -gon
• Septi- plus one
• Geometric prefix
• Twice tetra-
• Prefix with meter
• Eight: Prefix
• Prefix for eight
• Eight, for starters
• Hepta- plus one
• Penta- plus three
• Numeric prefix
• Bi- times four
• Beginning of eight words?