exformation
n.— «A Danish writer, Tor Norretranders, invented a term for this in his book The User Illusion: exformation. Exformation is short for “explicitly discarded information,” the information you strip out of a message because you know your reader already has it. The more you share with your reader, the less you have to say.» —“For Your Exformation” by Crawford Kilian Writing for the Web (B.C., Can.) Oct. 29, 2004. (source: Double-Tongued Dictionary)