a: the brand. made popular by Ralph Lauren and comes in a variety of styles and colors, and features a man on a horse playing the game, Polo
b: a style of shirt, sometimes called a collared shirt, that can be any brand from the expensive (but worth it) Polo RL, Lacoste and A+F to the less expensive mossimo, Cherokee and others
a: I went to the Polo Store on N. Michigan Ave.
b: I want this polo shirt, but shuld i get a RL Polo or a Lacoste polo.