Other forms: blotches
A blotch is an irregular discoloured patch. A red blotch, blotches on the skin, a blotch of ink.
The irregularity is the point: a spot is round and a blotch is not, which is why the word suits skin, ink and damp on a ceiling. It is probably a blend of blot and botch, both of which carry the same air of something gone wrong.
1nounblotchAn irregular discoloured patch.
“She had a red blotch on her neck after the insect bite.”
blotch is a mark.
Of uncertain origin, probably a blend of blot and botch.
unknown. Perhaps a blot and botch.
Etymology from Wiktionary, CC BY-SA