open - outs
- open association
- open community
- open group
- open system
- open to misconstruction
- open-class society
- open-cue situation
- open-ended class
- open-ended question
- open-mindedness
- openness
- operant
- operant behavior
- operant conditioning
- operant learning
- operant level
- operate
- operating capability
- operation
- operation of the mind
