blot 1 
(blŏt)
(blŏt)n.
1. A spot or a stain caused by a discoloring substance: a blot of paint.
2. An association of disgrace with one's character or reputation. See Synonyms at stain.
3.
a. A laboratory technique, such as a Southern blot analysis, that involves electrophoretically separating proteins or nucleic acids and transferring them to a membrane.
b. The membrane onto which these proteins or nucleic acids have been transferred.
v. blot·ted, blot·ting, blots
v.tr.
1. To soak up or dry with absorbent material. Often used with up: blotted the spill with a napkin; used a rag to blot up the paint.
2.
a. To make obscure or invisible; hide. Often used with out: clouds blotting out the moon.
b. To render invisible or unreadable by marking; obliterate. Often used with out: blotted out the names with a pen.
c. To remove or block from personal memory or public remembrance. Often used with out: "His death in the hour of victory blotted out his failings and left a heroic memory" (N.A.M. Rodger).
3. To spot or stain, as with a discoloring substance: Grass stains blotted the knees of his pants.
4. To bring moral disgrace to: an incident that blotted the senator's reputation.
v.intr.
1. To spill or spread in a spot or stain.
2. To become blotted, soaked up, or absorbed.
[Middle English.]