Definitions of learning by different Authors?

Learning is defined in a number of ways, some of the definitions of learning are as under : "Learning involves the acquisition of habits, knowledge and attitudes" .…Crow and Crow Learning is modification of behaviour through experience and training. "Learning as acquisition and retention." .Skinner "Learning is change in the individual tollowing upon changes in the environment" ...Peel "Learning is habit formation resulting from conditioning" ...Pavlov