The Collaborative International Dictionary of English v.0.48:

Occupation \Oc`cu*pa"tion\, n. [L. occupatio: cf. F.
   occupation.]
   1. The act or process of occupying or taking possession;
      actual possession and control; the state of being
      occupied; a holding or keeping; tenure; use; as, the
      occupation of lands by a tenant.
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   2. That which occupies or engages the time and attention.
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   3. Specfically: The principal business of one's life; the
      principal work by which one earns one's livelihood;
      vocation; employment; profession; calling; trade;
      avocation; as, these days many people continue to practice
      their occupation well into their seventies.
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            Absence of occupation is not rest.    --Cowper.
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   Occupation bridge (Engin.), a bridge connecting the parts
      of an estate separated by a railroad, a canal, or an
      ordinary road.
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   Syn: Occupancy; possession; tenure; use; employment;
        avocation; engagement; vocation; calling; office; trade;
        profession.
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