noun / verb
splotch
SPLAHCH/splɑtʃ/
An irregular patch of color, or marking something with such patches.
A purple splotch spreads unevenly across the pale cloth napkin.

Etymology
Splotch originally meant a broad, ill-defined spot, closely matching today's irregular stain or patch. It may blend spot, blot, and/or botch, but its formation is uncertain.
In context
One of the things you can see is a clue as to how this landscape formed in that dark diagonal splotch. That's called the North American wall
More examples
- The spilled juice leaves purple splotches on the tablecloth.
- She splotches the paper with blue and green paint.
- His apron is splotched with dried paint.
Forms
splotch · splotches · splotched · splotching
splotchy adjective — Covered with uneven patches of color.