protagonist /prə- or prō-tagˈə-nist/

1. Orig the chief actor, character or combatant
2. Now often applied to any (or in pl, all) of the main personages or participants in a story or event
3. (loosely) a champion or advocate

• osmosed
• osmoses
• osmosing
• osmosis
• osmotic
• osmotically
• osmotic pressure
• osmotic pressures
• osmous
• osmund
• osmunda
• Osmundaceae
• osmundas
• osmunds
• osnaburg
• osnaburgs
• O's of Advent
• osp
• osprey
• ospreys
• OSS
• ossa
• ossarium
• ossariums
• ossein