What is core?

Famous quotes containing the word core:

“The threadbare trees, so poor and thin,
They are no wealthier than I;
But with as brave a core within
They rear their boughs to the October sky.
Poor knights they are which bravely wait
The charge of Winter’s cavalry,
Keeping a simple Roman state,
Discumbered of their Persian luxury.”
—Henry David Thoreau (1817–1862)

“Individual science fiction stories may seem as trivial as ever to the blinder critics and philosophers of today—but the core of science fiction, its essence ... has become crucial to our salvation if we are to be saved at all.”
—Isaac Asimov (1920–1992)

“Avoiding humiliation is the core of tragedy and comedy.”
—John Guare (b. 1938)