When you thicken a liquid or when it thickens, it becomes stiffer and more solid. Thicken the broth with the cornflour Keep stirring until the sauce thickens
{f} make thick in consistency; become thick, condense; grow more intricate, become increasingly complex
People sometimes say `the plot thickens' when a situation or series of events is getting more and more complicated and mysterious. `Find anything?' he asked. `Yeah. The plot thickens,' I said. to become thick, or make something thick