1. begin to work, start getting serious about things
let's get down to work/business
'Get down to work' means to begin or get started on something. "We have a big project ahead of us, let's get to work!" 'Get down to business' means to begin to get serious or begin to discuss the matter at hand. You might use this after small talk at an important meeting to signal that you want to talk about something serious. Both of these expressions care used in social and professional situations.
If everybody is ready, let's get down to work.
I didn't get much done this morning, but now it's time to get down to work.