Noun
Sheffer stroke (plural Sheffer strokes)
(logic) The vertical bar symbol | denoting the NAND operation.
After section ✸8 the Sheffer stroke sees no usage. Source: Internet
An example would be the "grade up" character, which had to be made from a "delta" (shift-H) and a " Sheffer stroke " (shift-M). Source: Internet
Hence any formal system including the Sheffer stroke must also include a means of indicating grouping. Source: Internet