1. One of certain narrow, crooked valleys seen, by aid of the telescope, on the surface of the moon

Derived forms: rilles

Encyclopedia: Rille

• balking
• balkline
• balky
• ball
• ball and chain
• ball bearing
• ball boy
• ball carrier
• ball cartridge
• ball club
• ball fern
• ball field
• ball gown
• ball hawk
• ball lightning
• ball nettle
• ball nightshade
• ball of fire
• ball over
• ball valve
• ball-and-socket joint
• ball-breaker
• ball-buster
• ball-hawking
• ball-peen hammer