Which term describes the stars and blue background of the flag?

The term that describes the stars and blue background of the flag is "Canton or Union." In flag terminology, the "canton" refers to the upper hoist-side corner of the flag that typically contains a distinctive design, which in the case of the American flag, includes the blue field with white stars representing the states. This design element is crucial as it often serves as a unique identifier for the flag itself and symbolizes unity among the states.

Understanding the function and design of the canton is essential in flag design. While "field" may refer to the entire background of the flag that holds the primary design elements, it is less specific than "canton," which points directly to the section containing the stars. Similarly, terms like "hoist" refer to the side of the flag that is attached to the pole, and "fly" refers to the opposite side, or the part that flaps freely in the wind. Thus, "Canton or Union" is the precise term for the upper left section of the flag featuring the stars against a blue background.