1. Being or operating under the surface of the earth
   - subterranean 
2. Lying beyond what is openly revealed or avowed (especially being kept in the background or deliberately concealed)
   - subterranean, ulterior

See also: covert, subsurface

• Arabian tea
• Arabic
• Arabic alphabet
• Arabic language
• Arabic numeral
• arabica
• Arabidopsis
• Arabidopsis lyrata
• Arabidopsis thaliana
• arability
• arabinose
• Arabis
• Arabis Canadensis
• Arabis glabra
• Arabis turrita
• Arabist
• arable
• Araceae
• araceous
• Arachis
• Arachis hypogaea
• arachnid
• Arachnida
• arachnidian
• arachniography