"cave painting : (uncountable) The activity of applying pigments to the interior surfaces of caves to..."

“cave painting : (uncountable) The activity of applying pigments to the interior surfaces of caves to create images, especially when carried out in prehistoric times.
(uncountable) The paintings resulting from this activity regarded collectively, especially if prehistoric; cave art; (countable) a individual painting of this type.
Today, the third Saturday of October in 2020, was established by the Archaeological Institute of America as International Archaeology Day to celebrate archaeology and its contributions to society.”

- https://en.wiktionary.org/wiki/cave_painting#English

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