1. Not returned in kind
   - unanswered, unrequited

See also: nonreciprocal

• areca
• Areca catechu
• areca nut
• Arecaceae
• Arecidae
• areflexia
• aren't
• arena
• arena theater
• arenaceous
• arenaceous rock
• Arenaria
• Arenaria caroliniana
• Arenaria groenlandica
• Arenaria interpres
• Arenaria peploides
• Arenaria serpyllifolia
• Arenaria stricta
• Arenaria-Melanocephala
• Arenaviridae
• arenavirus
• Arendt
• Arenga
• Arenga pinnata
• arenicolous