To sway means to move slowly back and forth or side to side, like tall grass bending in the wind or tree branches rocking gently during a breeze. When you stand on a moving bus, you might sway as it turns corners. Dancers sway to music, shifting their weight from one foot to the other in rhythm.

The word also means to influence someone's opinion or decision. When you sway someone's thinking, you persuade them to see things differently. A powerful speech might sway voters to support a candidate. If you're trying to convince your parents to get a dog, you might sway them by showing how responsible you've become with your chores.

You can also be under someone's sway, meaning they have influence over you. A charismatic teacher might hold students under her sway through fascinating stories and clear explanations.

The noun form means influence or control: “The king held sway over the entire kingdom.” When someone holds sway, they have power or authority that affects how others think or act. Notice that sway suggests a gentler kind of influence than force or commands. It's about gradually shifting someone's position, like how wind gradually moves a tree.