Short answers, pulled from the story.
Sparśa is a Sanskrit term translated as contact, touching, sensation, or sense impression. It is defined as the coming together of a sense organ, a sense object, and sense consciousness, or vijnana.
In Pali, Sparśa is called phassa. Both terms describe the same coming together of a sense organ, a sense object, and consciousness.
The Theravada Abhidharma identifies Sparśa as one of seven universal mental factors.
The Mahayana Abhidharma identifies Sparśa as one of five universal mental factors.
Sparśa is the sixth link in the Twelve Nidānas, the chain of links Buddhist teaching uses to explain dependent origination. It is conditioned by the presence of the six sense-openings, and in turn conditions the arising of pleasant, unpleasant, or neutral feelings, or vedanā.
Buddhist teaching identifies six classes of contact: eye-contact, ear-contact, nose-contact, tongue-contact, body-contact, and mind-contact. Both the Theravada and Mahayana traditions recognize this same set of six.