(transitive) To ponder. / (transitive) To consider as a course of action.

To perform research and develop recommendations as part of a think tank.

(idiomatic) A group of people who collectively perform research and develop reports and recommendations on topics relating to strategic planning or public policy, and which is usually funded by corporate, government, or special interests.

(idiomatic) by the way; now that I think about it; indicates something brought to mind.

(transitive) To change one's mind concerning, especially to decide against.

(idiomatic, psychology) The illusion that what one would like to be true is actually true. / (idiomatic) Decision-making based on self-delusion.

(idiomatic) To reconsider, use judgement; to proceed with caution or thought.

(idiomatic) To create in one’s mind; to invent.

(idiomatic) To ponder or reflect on a subject.

(often derogatory) An in-depth article that discusses a topic thoroughly and elaborates the writer's point of view, to inspire deep thought related to the article's subject.