The attended stimulus is the specific object in the environment on which our attention is focused. In many cases, we might focus on stimuli that are familiar to us, such as the face of a friend in a crowd of strangers at the local coffee shop. In other instances, we are likely to attend to stimuli that have some degree of novelty.
From our earlier example, let's imagine that during your morning job you focus your attention on the duck floating in the nearby pond. The duck represents the attended stimulus. During the next step of the perceptual process, the visual process will progress.