Definition
To commit oneself to a task or activity that is employment-related or that requires serious effort or concentration.
How People Actually Use It
to begin seriously doing what you need to do; to begin to get serious; to begin to negotiate or conduct business; to start talking about the subject to be discussed; to apply oneself to serious matters; concentrate on work...
"There was a real determination to get down to business. The directors finally got down to business and decided to sign the contract."
Source: Urban Dictionary