Definition of "Occupation" :

noun: the act of occupying or taking possession of a building

"Occupation of a building without a certificate of occupancy is illegal."

noun: the principal activity in your life that you do to earn money

noun: any activity that occupies a person's attention

"He missed the bell in his occupation with the computer game."

noun: the control of a country by military forces of a foreign power

noun: the period of time during which a place or position or nation is occupied

"During the German occupation of Paris."