octodecimo /ok-tō-desˈi-mō/

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

A book with sheets so folded

• orbita
• orbital
• orbital engine
• orbital engines
• orbital motorway
• orbital motorways
• orbital road
• orbital roads
• orbitals
• orbited
• orbiter
• orbiters
• orbities
• orbiting
• orbits
• orbity
• orbs
• orby
• orc
• orca
• Orcadian
• orcas
• orcein
• orceins
• orch.