What does "in the house" mean here?

Native speaker’s answer
Rebecca
The phrase "best seat in the house" comes from when people watched plays in a theatre. Here, "house" refers to a "theatre house". Depending on where you would sit, you would get a better view of the performance. The "best seats" would usually go to important people, such as dignitaries or royalty. Now you can use it when you watch sports games, a movie, a concert, or something in a large general space and area where you can see everything clearly! By saying she has "the best seat in the house" it means she gets to sit comfortably and watch everything happening around her. Ex: The baseball game was so good! We had the best seats in the house. Ex: Jimmy's on the hill over there! It looks like he has the best seat in the house to watch the fireworks.