day·flow·er 
(dāflou′ər)
(dāflou′ər)n.
Any of various plants of the genus Commelina having delicate blue or purplish flowers that bloom for less than a day.
- cooperation
- cooperationist
- cooperative
- cooperatively
- cooperativeness
- cooperator
- Cooper pair
- Cooper's hawk
- Cooperstown
- co-opt
- co-optation
- co-optative
- co-option
- co-optive
- co-orbital
- coordinate
- coordinate bond
- coordinated universal time
- coordinately
- coordinateness
- coordinate system
- coordinating conjunction
- coordination
- coordination compound
- coordinative