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

• a/b
• ab
• ab-
• A&B
• AB
• Ab
• aba
• ABA
• abac
• abaca
• abacas
• abaci
• aback
• abacs
• abactinal
• abactinally
• abactor
• abactors
• abacus
• abacuses
• Abaddon
• a bad egg
• a bad hat
• a bad job
• a bad lot