hapax legomenon /hapˈaks le-gomˈə-non/ (Greek)

1. (literally) said once
2. A word or phrase that is found once only

• protoxylem
• protoxylems
• protozoa
• Protozoa
• protozoal
• protozoan
• protozoans
• protozoic
• protozoological
• protozoologies
• protozoologist
• protozoologists
• protozoology
• protozoon
• protract
• protracted
• protractedly
• protractible
• protractile
• protracting
• protraction
• protractions
• protractive
• protractor
• protractors