Sensory memory is a transitional memory function which is designed to quickly process the immense quantity of sensory information which we experience. Sensory memory typically lasts no more than a few seconds and often just a fraction of a second.
Humans have five senses - hearing, sight, smell, touch and taste. The purpose of sensory memory is to hold the sensation or 'impression' of the sensory information just long enough for us to basically figure out whether it was worth remembering. Incredibly, research hasn't conclusively proved that there is a sensory memory store for all five senses but clearly that is likely to be the case. Most sensory memory testing and research has been undertaken on Echoic Memory which concerns the sounds which we hear, Haptic Memory which concerns touch and iconic memory which concerns sight.