King James Dictionary 
OCCUPA'TION, n. L. occupatio.
1. The act of taking possession. 2. Possession a holding or keeping tenure use as lands in the occupation of AB. 3. That which engages the time and attention employment business. He devotes to study all the time that his other occupations will permit. 4. The principal business of one's life vocation calling trade the business which a man follows to procure a living or obtain wealth. Agriculture, manufactures and commerce furnish the most general occupations of life. Painting, statuary, music, are agreeable occupations. Men not engaged in some useful occupation commonly fall into vicious courses.
Webster's Dictionary 
(1): ( n.) 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.
(2): ( n.) That which occupies or engages the time and attention; the principal business of one's life; vocation; employment; calling; trade.
Vine's Expository Dictionary of NT Words 
Acts 18:3 Acts 19:25
Hastings' Dictionary of the New Testament 
See Labour, Work.