late 14c., originally "blemish," perhaps from Old Norse blettr "blot, stain," or from Old French blot, variant of bloc "block," or blestre "blister, lump, clump of earth."
early 15c., "to make blots;" mid-15c. "to blot out, obliterate" (words), from blot (n.). Related: Blotted; blotting.
The Northern, Southern, or Western blot analyses.
a stain or reproach (Job 31:7; Prov. 9:7). To blot out sin is to forgive it (Ps. 51:1, 9; Isa. 44:22; Acts 3:19). Christ's blotting out the handwriting of ordinances was his fulfilling the law in our behalf (Col. 2:14).