cave
noun
a hollow in the earth, especially one opening more or less horizontally into a hill, mountain, etc.
Used to describe an action that was ongoing continuously in the past up until another past event interrupted it.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The empire, which for some time had been caving in at the center, was now everywhere crumbling at the edges.
From Maximilian in Mexico A Woman's Reminiscences of the French Intervention 1862-1867 by Sara Yorke Stevenson