v.1. To assume a sitting position; take a seat: She sat down to eat. Let's sit down in front of the television.
2. To cause someone to assume a sitting position, especially in a mandatory way: The principal sat me down and began lecturing. You need to sit down all your grandchildren some day and tell them your wonderful story.
3. sit down with To meet with someone in order to deliberate together or compare views: The foreign ambassador sat down with the president.