: to become aware of or give attention to something or someone : to observe or treat something or someone with special attention
… one Saturday in October 1984, San Francisco coach Bill Walsh flipped on the TV to watch college football, saw Rice on the highlights and took notice. Peter King
—often used with of
It was a while before anyone took notice of the change.… suggests that the academy is at last beginning to sit up and take notice of how the world really works. Terry TeachoutThey took no notice of him. [=they ignored him]