mid-15c., "obliteration," verbal noun from blot (v.). Blotting-paper (1510s), rough and spongy, is used to absorb excess ink from freshly written paper without blurring.
Entries linking to blotting
blot v.
early 15c., "to make blots (with ink), disfigure with blots," also figurative; mid-15c. "to blot out, obliterate" (words), from blot (n.). Related: Blotted; blotting.