1. (chemistry) hydrogen
   - hydro- 
2. Water
   - hydro-

Encyclopedia: Hydr-

• coop
• coop in
• coop up
• cooper
• Cooper Union
• Cooper Union for the Advancement of Science and Art
• Cooper's hawk
• cooperage
• cooperate
• cooperation
• cooperative
• cooperatively
• cooperativeness
• cooperator
• Cooperstown
• coordinate
• coordinate axis
• coordinate bond
• coordinate clause
• coordinate geometry
• coordinate system
• coordinated
• coordinated universal time
• coordinately
• coordinating