1. To be a member of some group of officials. She's been asked to sit on the president's foreign intelligence council. I sat on the board of directors for a number of years, but I did not have an active role in the company.

2. To suppress, repress, stifle, or hide something. The company sat on reports indicating a health risk in their products for nearly ten years until sick customers started coming forward with lawsuits. The government is clearly sitting on evidence that would clear the man's name.

3. To join or meet in order to discuss, confer, or consult about something. The city council promised to sit on the issue at its next meeting. They asked me to sit on the case because of my familiarity with the topic.

4. To delay, postpone, or avoid using something. With the amount of money that company's sitting on, you'd think they could figure out a product that actually works properly! They're sitting on some of the best talent in the industry, and it's all just going to waste.

5. To delay, postpone, or avoid taking some action or making some decision. It's a lot of money to spend on a car—let me sit on it for a day or two, and I'll give you a final decision then. The boss said she was sitting on my idea until more sales figures came in.