tertium quid /tûrˈsh(i-)əm kwid or terˈti-ŭm/)

1. A third unknown thing related to two specific known things
2. Something intermediate between opposites
3. The third person in the eternal triangle

• phrenologizing
• phrenology
• phrensical
• phrensy
• phrentick
• phrontisteries
• phrontistery
• Phrygian
• Phrygian cap
• Phrygian mode
• pHs
• phthalate
• phthalates
• phthalein
• phthaleins
• phthalic
• phthalin
• phthalins
• phthalocyanin
• phthalocyanine
• phthalocyanines
• phthalocyanins
• phthiriases
• phthiriasis
• phthises