- occupation health
- occupation health safety management system
- Occupation Information Network
- occupation number
- occupation number operator
- occupation number representation
- occupation pension
- occupation probability
- occupation prohibition
- occupation ratio
- occupation time
- occupied band
- occupied orbital
- occupied state
- Occupy Wall Street
- occurrence
- occurrence net
- occurrence of a lexeme
- occurrence of speech sound
- occurrence problem
- occurrence rate
- occurrences of igneous rocks
- OC curve
- OCD
- OCDM model