"To start a discussion" means to begin a conversation or talk about a particular topic to gather different opinions and ideas from others. Full definition
We have also started discussions with all our other partners in the digital book world. (nelsonagency.com)
Instead of starting the discussion on a critical note about his preference, she is careful to suggest that they consider their future needs before deciding. (divorcesource.com)
Start a discussion of how this activity relates to the idea of teamwork — for example, the students need to work together and not let others down. (educationworld.com)