The Union flag, which is called the Stars and Stripes, symbolized solidarity and patriotism

https://jaidenbnki358.clearhavendigest.com/posts/the-evolution-of-civil-war-flags-designs-and-meanings

The Union flag, referred to as the Stars and Stripes, symbolized harmony and patriotism, presenting 13 stripes and a box of blue with stars that represented both nation inside the union.