Organization

Most businesses must accomplish similar functions regardless of size, legal structure or industry. These functions are often organized into departments. Common departments include (but are not limited to):

Human Resources
Typically responsible for hiring, firing, payroll, benefits, etc.
Finance
responsible for managing the enterprises financial resources[1]

Budgeting and forecasting
planning how the enterprise wants things to happen
Cash and treasury management
ensuring the enterprise has money when it's needed
Accounts payable and receivable
ensuring the enterprise receives what it's owed and pay what it owes
Tax planning/filing and reporting
meeting obligations to the government
Risk management
ensuring the enterprise doesn't get surprised by something unfavorable
External and internal (management) reporting
providing visibility into the enterprise for those who need it through financial reporting and other types of reporting

Marketing and sales
responsible for selling the business' goods or services to the customer and for managing the relationships with the customer

Marketing
Typically responsible for promoting interest in, and generating demand for, the business' products or services, and positioning them within the market
Sales
finding likely purchasers and obtaining their agreement (known as a contract) to buy the business' products or services

Operations
makes the product or delivers the service

Production
produces the raw materials into the delivered goods, if they require processing
Customer service
supports customers who need help with the goods or services

Procurement
responsible for acquiring the goods and services necessary for the business. Sometimes organized as:

Strategic sourcing
determines the business' needs and plans for acquiring the necessary raw materials and services for the business
Purchasing
processes the purchase orders and related transactions

Research and Development
tests to create new products and to determine their viability (e.g. pilot plants)
Information Technology
manages the business' computer and data assets
Communications/Public Relations
responsible for communicating to the outside world
Administration
provides administrative support to the other departments (such as typing, filing, etc.)
Internal Audit
an independent control function typically accountable to the Board of Directors for reporting on the proper functioning of the other departments

Management is sometimes listed as a "department" but typically refers to the top level of leadership within the business regardless of their functional role.