centerpiece
The main thing in the middle that gets the most attention.
A centerpiece is something placed in the middle of a table, usually for decoration. At Thanksgiving dinner, you might see a centerpiece of autumn leaves and small pumpkins. At a wedding reception, each table might have a centerpiece of flowers in a vase. The centerpiece draws your eye when you sit down and makes the table feel special and complete.
The word also describes the most important or prominent part of something larger. If your school holds a fundraiser with games, raffles, and performances, the talent show might be the centerpiece of the event: the main attraction that everything else revolves around. When a museum designs a new exhibit, they often choose one spectacular object as the centerpiece, placing it where visitors can't miss it.
In both meanings, a centerpiece occupies the central position and commands attention. It's what you notice first, what brings everything together, and what people remember most. The centerpiece of your science fair project might be a working model that demonstrates your hypothesis. The centerpiece of your argument in a debate is your strongest, most convincing point.