Division-Something, such as a boundary or partition, that serves to divide or keep separate. One of the parts, sections, or groups into which something is divided.
Section- A part or division of a book, newspaper, etc. A numbered paragraph of a writing, a law, etc. Any distinct, constituent part: a bookcase in five sections, various sections of society.
Unit-A group regarded as a distinct entity within a larger group. Any fixed quantity, amount, distance, measure, etc. used as a standard
Department- A separate part, division, or branch, as of a government, business, or school: the police department, the accounting department, the history department.
Industry- Any particular branch of productive, esp. manufacturing, enterprise: the paper industry. Any large-scale business activity: the tourist industry
The accounting division is the largest department of our company, since we are a financial firm.
This section of the city is very crowded. My apartment is unit number five on the tenth floor. The tourism industry is the largest growing section of our economy.
I hope that helps.
Scott