Metagram

 Metagram

a riddle in which the change of the initial letter produces a series of words of different meanings; from meta , implying change, and gramma , a letter. Thus:
I cover your head; change my head, and I set you to sleep; change it again and again, and with every change comes a new idea.—Cap, Nap, Gap, Sap, Hap, Map, Lap, Pap, Rap, Tap. This kind of riddle is also known as word-capping.


Gunpowder Made By a Monk at Cologne A.D.1330.