The sticky option indicates the borders where the widget should stick, expressed in cardinal directions: north, south, west and east. These values are represented by the Tkinter constants  tk.N, tk.S, tk.W, and  tk.E, as well as the combined versions tk.NW, tk.NE, tk.SW, and tk.SE.

For example, sticky=tk.N aligns the widget to the top border of the cell (north), whereas sticky=tk.SE positions the widget in the bottom-right corner of the cell (south-east).

Since these constants represent their corresponding lowercase letters, we shorthanded the tk.N + tk.S + tk.W + tk.E expression with the "nswe" string. This means that the widget should expand both horizontally and vertically—similar to the fill=tk.BOTH option of the Pack geometry manager.

If no value is passed to the sticky option, the widget is centered within the cell.