What side of the flag is closest to the flagpole called?

The side of the flag that is closest to the flagpole is referred to as the "hoist." This term is used specifically to denote the part of the flag that is attached to the halyard for hoisting and lowering the flag. In flag terminology, the hoist plays a critical role because it supports the flag's position and maintains its display when it is raised on a flagpole.

The other terms in the context of flags represent different parts or concepts. The fly refers to the side of the flag that is farthest from the flagpole, while the canton is the upper left corner of a flag, typically reserved for a symbol or emblem. The field refers to the main part of the flag that serves as the background. Understanding the terminology related to flags is essential for proper flag display and etiquette, making "hoist" the correct answer to this question.