penstock /penˈstok/

1. A sluice
2. (in a hydroelectric or other plant) a valve-controlled water conduit

• rapturizing
• rapturous
• rapturously
• rapturousness
• rara avis
• ra-ra skirt
• ra-ra skirts
• rare
• rare bird
• rare birds
• rarebit
• rarebits
• rare earth
• rare-earth element
• rare earths
• raree-show
• raree-shows
• rarefaction
• rarefactions
• rarefactive
• rarefiable
• rarefied
• rarefies
• rarefy
• rarefying