octodecimo /ok-tō-desˈi-mō/

1. Having eighteen leaves to the sheet
2. Contracted 18mo, often read eighteenmo

A book with sheets so folded

• photo-emission
• photo-engraving
• photo-essay
• photo-essays
• photo-etching
• photo finish
• photo finishes
• photofission
• photofissions
• Photofits
• Photofit®
• photoflood
• photoflood lamp
• photoflood lamps
• photofloods
• photog
• photog.
• photogen
• photogene
• photogenes
• prismoid
• prismoidal
• prismoids
• prisms
• prismy